Enhancing a cancer prevention and control curriculum through interactive group discussions.

The Principles and Practice of Cancer Prevention and Control course (Principles course) is offered annually by the National Cancer Institute Cancer Prevention Fellowship Program. This 4-week postgraduate course covers the spectrum of cancer prevention and control research (e.g., epidemiology, laboratory, clinical, social, and behavioral sciences) and is open to attendees from medical, academic, government, and related institutions across the world. In this report, we describe a new addition to the Principles course syllabus, which was exclusively a lecture-based format for over 20 years. In 2011, cancer prevention fellows and staff designed and implemented small group discussion sessions as part of the curriculum. The goals of these sessions were to foster an interactive environment, discuss concepts presented during the Principles course, exchange ideas, and enhance networking among the course participants and provide a teaching and leadership opportunity to current cancer prevention fellows. Overall, both the participants and facilitators who returned the evaluation forms (n=61/87 and 8/10, respectively) reported a high satisfaction with the experience for providing both an opportunity to explore course concepts in a greater detail and to network with colleagues. Participants (93%) and facilitators (100%) stated that they would like to see this component remain a part of the Principles course curriculum, and both groups provided recommendations for the 2012 program. The design, implementation, and evaluation of this initial discussion group component of the Principles course are described herein. The findings in this report will not only inform future discussion group sessions in the Principles course but may also be useful to others planning to incorporate group learning into large primarily lecture-based courses.

Behavioral evidence for the presence of a sex pheromone in male Phlebotomus papatasi scopoli (Diptera: Psychodidae).

Phlebotomus papatasi (Diptera: Psychodidae) is the Old World sand fly vector of zoonotic cutaneous leishmaniasis caused by Leishmania major (Trypanosomatidae: Kinetoplastida), a debilitating and disfiguring protist parasitic disease prevalent throughout southern Mediterranean countries, the Middle East, as well as southern and eastern European countries, where it is regarded as a serious public health problem. Little is known of the mating ecology of P. papatasi, and, in particular, the role (if any) of pheromones is not known. In this laboratory- and field-based study, we have shown that a male-produced sex pheromone exists in P. papatasi. Young female P. papatasi are attracted to the headspace volatiles of small groups of males, males and females together, but not females alone. Males were not attracted to males, females, or mixed groups of males and females in the laboratory. Larger groups of males or males and females together were repellent in the laboratory study. Field experiments showed that Centers for Disease Control (CDC) light traps baited with small groups of males and females together were attractive to females, but not males. CDC traps baited with large groups of males and females together caught significantly fewer females and males than the control traps; however, the proportion of females caught compared with males overall was much higher than with CDC traps baited with small numbers of males and females. These results suggest that females may be attracted in preference to males to the vicinity of the baited traps and are highly sensitive to the concentration of male pheromone. It also suggests that P. papatasi mating behavior is fundamentally different from that of Lutzomyia longipalpis, where large mating aggregations of males and females occur.

Synthetic sex pheromone attracts the leishmaniasis vector Lutzomyia longipalpis (Diptera: Psychodidae) to traps in the field.

Improving vector control remains a key goal in reducing the world's burden of infectious diseases. More cost-effective approaches to vector control are urgently needed, particularly because vaccines are unavailable and treatment is prohibitively expensive. The causative agent of American visceral leishmaniasis (AVL), Leishmania chagasi, Cunha and Chagas (Kinetoplastida: Trypanosomatidae), is transmitted between animal and human hosts by blood-feeding female sand flies attracted to mating aggregations formed on or above host animals by male-produced sex pheromones. Our results show the potential of using synthetic pheromones to control populations of Lutzomyia longipalpis Lutz and Neiva (Diptera: Psychodidae), the sand fly vector of one of the world's most important neglected diseases, AVL. We showed that a synthetic pheromone, (+/-)-9-methylgermacrene-B, produced from a low-cost plant intermediate, attracted females in the laboratory. By formulating dispensers that released this pheromone at a rate similar to that released by aggregating males, we were able to attract flies of both sexes to traps in the field. These dispensers worked equally well when deployed with mechanical light traps and inexpensive sticky traps. If deployed effectively, pheromone-based traps could be used to decrease AVL transmission rates through specific targeting and reduction of L. longipalpis populations. This is the first study to show attraction of a human disease-transmitting insect to a synthetic pheromone in the field, showing the general applicability of this novel approach for developing new tools for use in vector control.

Sandfly pheromones. Their biology and potential for use in control programs.

Lutzomyia longipalpis (Diptera: Psychodidae) is the vector of Leishmania chagasi the causative agent of visceral leishmaniasis (VL) in South and Central America, particularly Brazil, where the greatest incidence occurs. The disease is fatal if untreated. Although huge efforts have been made to control VL the incidence is increasing. Vector control remains an important element of disease control but residual spraying and other strategies have failed to make any lasting impact. Manipulation of sandfly chemical communication offers the opportunity to add new techniques and tools to reduce sandfly populations and thereby reduce Leishmania transmission. This paper reports the current understanding of several areas of sandfly chemical ecology and their prospects for application.

Host odor synergizes attraction of virgin female Lutzomyia longipalpis (Diptera: Psychodidae).

The sand fly Lutzomyia longipalpis Lutz & Neiva (Diptera: Psychodidae) is the principle vector of Leishmania chagasi/infantum Cunha and Chagas, the causative agent of visceral leishmaniasis. The disease is transmitted by blood-feeding females, which seek aggregations of males above potential hosts both to mate and blood-feed. Pheromones produced by male sand flies could potentially be used as lures in L. longipalpis control programs. We investigated whether attraction of male and female sand flies to pheromone could be increased by addition of host odor. Pheromone was attractive to females in the absence of host odor, although a 10-fold increase in concentration did not increase numbers attracted or reduce the proportion of flies not responding during trials. Odors from Syrian hamsters, Mesocricetus auratus, were more attractive to females than air when presented without sex pheromone, but this effect was masked by hexane, suggesting attraction to host odor alone may be relatively weak. Addition of hamster odor both increased the number of virgin female L. longipalpis attracted to sex pheromone (relative to a solvent control) and reduced the number of nonresponders, indicating that host odor may have both a synergistic and activating effect. Male sand flies were not attracted to pheromone with or without host odor, although addition of pheromone did counteract an apparent avoidance of host odor combined with a hexane control. These results indicate L. longipalpis pheromones function primarily to attract females and that their efficacy as lures may be increased through addition of host odor, or by deploying traps in the vicinity of host animals.

After infection with Leishmania infantum, Golden Hamsters (Mesocricetus auratus) become more attractive to female sand flies (Lutzomyia longipalpis).

In Brazil, human and canine visceral leishmaniasis is caused by infection with Leishmania infantum, a Protist parasite transmitted by blood-feeding female Lutzomyia longipalpis sand flies. The objective of this study was to determine if the odour of hamsters, infected with Le. infantum, was more attractive than the odour of the same hamsters, before they were infected. The attractiveness of odour collected from individual hamsters (n = 13), before they were infected, was compared in a longitudinal study, with the attractiveness of the odour of the same hamster in a Y-tube olfactometer bioassay, at a late stage of infection. The odour of six of the golden hamsters was significantly more attractive to 50% of the female sand flies at the end of infection compared to before infection and the odour of four of the golden hamsters was significantly more attractive to 75% of the female sand flies at the end of infection. These results strongly indicate that hamsters infected with Le. infantum become significantly more attractive to a greater proportion of female sand flies as the infection progresses.

Some effects of deoxycholate administration on the metabolism of cholesterol in man.

Hypercholesterolemic subjects in a metabolic ward were kept under uniform dietary conditions until constant levels of serum cholesterol were observed. Oral dosage with deoxycholate (1.5 to 3 g daily for a period of 4 to 10 weeks) resulted in a marked reduction of serum cholesterol concentration. Studies with 14C-labeled cholesterol demonstrated that deoxycholate administration decreased absorption of cholesterol from the human intestinal tract. In these subjects, the turnover rate of serum cholesterol was more rapid during therapy with deoxycholate than during control periods. Deoxycholate appeared to influence the intestinal flora as assessed indirectly by analysis of the types of neutral sterols eliminated with the feces. Decreased synthesis of cholesterol during deoxycholate administration uas demonstrated in a study with 14C-mevalonate. It is concluded that deoxycholic acid can have an important role in the regulation of cholesterol metabolism in humans.

Fine-root respiration in a loblolly pine and sweetgum forest growing in elevated CO2.

• The loss of carbon below-ground through respiration of fine roots may be modified by global change. Here we tested the hypothesis that a reduction in N concentration of tree fine-roots grown in an elevated atmospheric CO2 concentration would reduce maintenance respiration and that more energy would be used for root growth and N uptake. We partitioned total fine-root respiration (RT ) between maintenance (RM ), growth (RG ), and N uptake respiration (RN ) for loblolly pine (Pinus taeda) and sweetgum (Liquidambar styraciflua) forests exposed to elevated CO2 . • A substantial increase in fine-root production contributed to a 151% increase in RG for loblolly pine in elevated CO2 . Root specific RM for pine was 24% lower under elevated CO2 but when extrapolated to the entire forest, no treatment effect could be detected. • R G (< 10%) and RN (< 3%) were small components of RM in both forests. Maintenance respiration was the vast majority of RT , and contributed 92% and 86% of these totals at the pine and sweetgum forests, respectively. • The hypothesis was rejected because the majority of fine-root respiration was used for maintenance and was not reduced by changes in root N concentration in elevated CO2 . Because of its large contribution to RT and total soil CO2 efflux, changes in RM caused by warming may greatly alter carbon losses from forests to the atmosphere.

Enhanced sandfly attraction to Leishmania-infected hosts.

We report that hamsters infected with Leishmania infantum are more attractive to female sandflies in bioassays. Entrained odours from infected animals were shown by gas chromatography to contain peaks absent from uninfected individuals. Implications of enhanced transmission, potential for developing novel diagnoses and the significance to epidemiological models are discussed.

Copulation songs in three siblings of Lutzomyia longipalpis (Diptera: Psychodidae).

We present the results of recording male courtship songs of the sandfly Lutzomyia longipalpis. The striking differences in the songs from 3 Brazilian populations of this sandfly with 3 distinct male pheromones support the 3 sibling species previously proposed based on this characteristic.

Coexistence and interference between a native perennial grass and non-native annual grasses in California.

Little is known about the potential for coexistence between native and non-native plants after large-scale biological invasions. Using the example of native perennial bunchgrasses and non-native annual grasses in California grasslands, we sought to determine the effects of interference from non-native grasses on the different life stages of the native perennial bunchgrass Nassella pulchra. Further, we asked whether N. pulchra interferes with non-native annual grasses, and whether competition for water is an important component of these interspecific interactions in this water-limited system. In a series of field and greenhouse experiments employing neighbor removals and additions of water, we found that seedling recruitment of N. pulchra was strongly seed-limited. In both field and greenhouse, natural recruitment of N. pulchra seedlings from grassland soil was extremely low. In field plots where we added seeds, addition of water to field plots increased density of N. pulchra seedlings by 88% and increased total aboveground N. pulchra seedling biomass by almost 90%, suggesting that water was the primary limiting resource. In the greenhouse, simulated drought early in the growing season had a greater negative effect on the biomass of annual seedlings than on the seedlings of N. pulchra. In the field, presence of annuals reduced growth and seed production of all sizes of N. pulchra, and these effects did not decrease as N. pulchra individuals increased in size. These negative effects appeared to be due to competition for water, because N. pulchra plants showed less negative pre-dawn leaf water potentials when annual neighbors were removed. Also, simply adding water caused the same increases in aboveground biomass and seed production of N. pulchra plants as removing all annual neighbors. We found no evidence that established N. pulchra plants were able to suppress non-native annual grasses. Removing large N. pulchra individuals did not affect peak biomass per unit area of annuals. We conclude that effects of interference from non native annuals are important through all life stages of the native perennial N. pulchra. Our results suggest that persistence of native bunchgrasses may be enhanced by greater mortality of annual than perennial seedlings during drought, and possibly by reduced competition for water in wet years because of increased resource availability.

A fourth chemotype of Lutzomyia longipalpis (Diptera: Psychodidae) from Jaibas, Minas Gerais State, Brazil.

Lutzomyia longipalpis (Lutz and Neiva) is a species complex of Lutzomyia pseudolongipalpis (Arrivillaga and Feliciangeli) and at least three other as yet undefined siblings. Isozyme and mitochondrial studies of allopatric populations across Central and South America have suggested the presence of four "clades" that have been hypothesized to have arisen mainly because of geographical isolation mechanisms. Parallel studies of sexual behavior as well as cross-mating and genetic analysis, of both allopatric and sympatric populations, suggest at least four sibling species that do not seem to correspond to the defined four "clades." In an effort to understand this apparent discrepancy, sympatric populations of L. longipalpis from a single South American country, Brazil, are being studied. In Brazil, three putative species can be identified by their male-produced sex pheromones: (S)-9-methylgermacrene-B, 3-methyl-a-himachalene, and a cembrene. We report here that analysis by coupled gas chromatography-mass spectrometry shows that L. longipalpis from Jaibas, Minas Gerais State, Brazil, occurs as two sympatric sex pheromone chemotypes. One chemotype is the cembrene type previously recorded in a L. longipalpis population from Sobral, Ceará State, Brazil, and the other is a new cembrene isomer not previously observed in L. longipalpis. The finding of this new chemotype strongly suggests that the L. longipalpis species complex in Brazil consists of four members rather than the three previously recognized and confirms previous analysis of genetic variation that had suggested the presence of a complex in Brazil.

Integument and sensillum auriforme of the opisthosoma of Rhipicephalus appendiculatus (Acari:Ixodidae).

The opisthosomal integument and sensilla auriformia of Rhipicephalus appendiculatus Neumann larvae, nymphs, females and males, both unfed, fed, and during molt, were examined by light and electron microscopy in relation to semiochemical production. The integument consists of epidermis, endocuticle, exocuticle, epicuticle, a superficial wax layer and a variable additional deposit. The integument of immature instars and females grows greatly during feeding. The integument is traversed by pore canals from the epidermis to the outer wax canals. The epidermis can secrete material to the exterior by way of the pore canals and wax canals. The sensillum auriforme is a common disk-shaped organ, with a complex internal chamber open to the exterior by way of a pore. It has no apparent secretory capacity and is of presumed sensory function. It is located in the integument of scutum and alloscutum of all instars.

Integumental glands of the tick Rhipicephalus appendiculatus (Acari:Ixodidae) as potential producers of semiochemicals.

The opisthosomal integument and associated secretory organs of Rhipicephalus appendiculatus Neumann larvae, nymphs, females and males, both unfed and fed were examined by light and electron microscopy. Type 1 dermal glands were found on the alloscutum and scutum of all ticks. They were undeveloped in unfed ticks and reached full development in engorging ticks. They produced secretory granules from 2 glandular cells but without accumulation of a reservoir of secreted material. Type 2 dermal glands were found in all ticks, with pores on the alloscutum, edge of scutum, and on anal plates. These glands produced secretion during feeding and accumulated large reservoirs of secreted material that were present in engorging, recently detached and questing ticks. Spiracular glands were found in all ticks below the spiracle plate. They produced small amounts of secretion and had pores to the exterior by way of spiracle goblets. No obvious cycle of secretory activity was recorded. Foveal glands were present and produced secretions in nymphs, females, and males. They were largest in females with an accumulation of secretory vesicles in feeding ticks. The potential function of these glands is discussed in the context of the chemical ecology of this tick.

The effect of 5,8,11,14-eicosatetraynoic acid on lipid metabolism.

The purpose of this presentation is to review the current state of knowledge regarding 5,8,11,14-eicosatetraynoic acid (ETYA, Ro 3-1428) and its effects on lipid metabolism. Accordingly, the topics discussed include hypocholesterolemic and dermatological studies involving ETYA in both animals and man, as well as the effects of ETYA on desaturase enzymes. Metabolic studies involving ETYA are also noted. Primary interest is focused on the effects of ETYA on selected processes of arachidonate metabolism, and the effect of ETYA on inflammation, platelet aggregation and tumor growth are discussed, keeping in mind the relevance of arachidonate metabolism to these processes.

Separation of neutral lipid, free fatty acid and phospholipid classes by normal phase HPLC.

Normal phase high performance liquid chromatography methods are described for the separation of neutral lipid, fatty acid and five phospholipid classes using spectrophotometric detection at 206 nm. Separations were accomplished in less than 10 min for each lipid class. A mobile phase consisting of hexane/methyltertiarybutylether/acetic acid (100:5:0.02) proved effective in separating cholesteryl ester and triglyceride with recoveries of 100% for radiolabeled cholesteryl oleate and 98% for radiolabeled triolein. Free fatty acid and cholesterol were separated by two different mobile phases. The first, hexane/methyltertiarybutylether/acetic acid (70:30:0.02) effectively separated free fatty acids and cholesterol, but did not separate cholesterol from 1,2-diglyceride. A mobile phase consisting of hexane/isopropanol/acetic acid (100:2:0.02) effectively separated free fatty acid, cholesterol, 1,2-diglyceride and 1,3-diglyceride. Recoveries of oleic acid and cholesterol were 100% and 97%, respectively. Five phospholipid classes were separated using methyltertiarybutylether/methanol/aqueous ammonium acetate (pH 8.6) (5:8:2) as the mobile phase. The recoveries of phosphatidylinositol, phosphatidylethanolamine, phosphatidylcholine, sphingomyelin and lysophosphatidylcholine were each greater than 96%.

Rapid separation of neutral lipids, free fatty acids and polar lipids using prepacked silica Sep-Pak columns.

A method is described for the separation of neutral lipid, free fatty acid and polar lipid classes using small (600 mg), prepacked silica Sep-Pak columns. Combinations of hexane and methyltertiarybutylether were used to progressively elute cholesteryl ester first then triglyceride from the column. After column acidification, fatty acids were eluted followed by cholesterol. Recoveries of these lipids were 96% or greater. Polar lipids were eluted from the column using combinations of methyltertiarybutylether, methanol and ammonium acetate. Phospholipid classes could not be separated completely from each other. Phosphatidylethanolamine and phosphatidylinositol eluted together, whereas the more polar phosphatidylcholine, sphingomyelin and lysophosphatidylcholine were eluted as a second fraction. Recoveries of each phospholipid was greater than 98%.

Hupolipidemic activity of (--)-hydroxycitrate.

The influence of (--)-hydroxycitrate, a potent competitive inhibitor of adenosine triphosphate (ATP) citrate lyase, on serum triglyceride and cholesterol levels, and in vitro and in vivo rates of hepatic fatty acid and chloesterol synthesis was investigated in normal and hyperlipidemic rat model systems. (--)-Hydroxycitrate reduced equivalently the biosynthesis of triglycerides, phospholipids, cholesterol, diglycerides, cholesteryl esters, and free fatty acids in isolated liver cells. In vivo hepatic rates of fatty acid and cholesterol synthesis determined in meal-fed normolipidemic rats were suppressed significantly by the oral administration of (--)-hydroxycitrate for 6 hr, when control animals exhibited maximal rates of lipid synthesis; serum triglyceride and cholesterol levels were significantly reduced by (--)-hydroxycitrate. In two hypertriglyceridemic models-the genetically obese Zucker rat and the fructose-treated rat-elevated triglyceride levels were due, in part, to enhance hepatic rates of fatty acid synthesis. (--)-Hydroxycitrate significantly reduced the hypertriglyceridemia and hyperlipogensisi in both models. the marked hypertriglyceridemia exhibited by the triton-treated rat was only minimally due to increased hepatic lipogenesis;(--)-hydroxycitrate significantly inhibited both serum triglyceride levels and lipogenesis in this model.

Fatty acid concentrations in synchronous cultures ofChlorella pyrenoidosa, grown in the presence and absence of glucose.

Total cellular fatty acids, of a high-temperature strain ofChlorella pyrenoidosa, were measured during a synchronous growth cycle in continuous light in the presence and absence of glucose.The fatty acid composition, consisting of saturated monoenoic, dienoic, and trienoic C(16) and C(18) fatty acids, remained essentially the same whether or not the cells were grown on glucose.Nearly all of the fatty acids increased irregularly in concentration during the growth cycle, showing a periodism during the prenuclear and cell-division stages of growth. Cultures exposed to glucose showed a more pronounced drop in the concentration of most of the fatty acids during both stages.None of the fatty acid concentrations, some of which have been implicated in the Hill reaction of a number of photosynthetic organisms, reflected the periodism in photosynthetic activity which was previously observed during the synchronous growth cycle of this organism.The changes in fatty acid concentration are discussed with relation to concurrent metabolic and cytological changes during cell maturation in this organism.

Fatty acid and cholesterol synthesis from specifically labeled leucine by isolated rat hepatocytes.

Hepatocytes isolated from female rats meal-fed a high-glucose diet were incubated in Krebs-Henseleit bicarbonate medium containing 16.5 mM glucose, 3H2O, and 14C-labeled amino acids (-)-Hydroxycitrate depressed the incorporation of 3H2O and [14C] alanine into fatty acids and cholesterol. Incorporation of [U-14C]leucine into lipids was not affected but incorporation of 3H2O into lipids was decreased significantly by (-)-hydroxycitrate. (-)-Hydroxycitrate depressed the incorporation of radioactivity from [2-14C]leucine into fatty acids and cholesterol by 61 and 38%, respectively, and stimulated the incorporation of radioactivity from [4,5-3H]leucine 35 and 28%. As [2-14C]leucine labels the acetyl-CoA pool and [4,5-3H]leucine labels the acetoacetate pool, it was concluded that mitochondrial 3-hydroxy-3-methylglutaryl-CoA is not incorporated intact into cholesterol, and that acetoacetate can be activated effectively in the liver cytosol for support of cholesterol and fatty acid synthesis.