Abstract P2-09-24: Information preferences and short-term psychological responses to multiplex genetic testing among individuals at risk for hereditary breast cancer

Background: Multiplex genetic testing involves the simultaneous analysis of a panel of known cancer susceptibility genes. Although efficient and cost-effective, multiplex testing presents several challenges for patients and clinicians: these tests provide information about high and moderate penetrance genes of varying clinical utility, patients cannot choose which specific genes are tested, and multiple variants of uncertain significance can be identified at once. Multiplex testing is being increasingly integrated into clinical care, yet little is known about patients' preferences, uptake, or psychological responses to these tests.

Methods: To address this gap, we examined two data sources: Sample A) a cross-sectional clinical ascertainment of 189 patients evaluated for hereditary breast and other cancer syndromes (89% female), and Sample B) an ongoing prospective research study of multiplex testing among 194 breast cancer patients and survivors who previously received uninformative BRCA1/2 results (99% female, 84% white, ages 27-76, 60% had BRCA1/2 testing in the past year).

Results: In Sample A, 32% declined clinical multiplex testing in favor of more targeted testing. Female patients were more likely than males to decline (p=0.004). Self-reported reasons for declining included: concerns about uncertain clinical utility of moderate penetrance genes (51% of patients) and variants of uncertain significance (38%), feeling emotionally overwhelmed (23%), and not seeing the value of multiplex testing (20%). In Sample B, participants were allowed to select which information to receive from a multiplex test; 16% chose to learn less than all of the information available (e.g., not genes unrelated to breast/ovarian cancer, not genes without established clinical utility, not CDH1 or TP53). Information preferences were unrelated to demographic (age, race, time since cancer diagnosis and BRCA1/2 testing) and self-reported psychological factors (baseline genetic testing-related distress, uncertainty, and positive experiences; anxiety; depression). Participants who chose to learn all possible information reported greater concerns about their children's cancer risk than did those who chose to learn less information (p=0.01). Participants reported a small increase in both genetic testing-related distress and positive experiences from before testing to 1 week after receiving results (p<0.001). In multivariable analyses controlling for baseline psychological functioning, only non-white race was consistently associated with significantly increased post-result anxiety, depression, and genetic testing-related distress and uncertainty. Participants who had BRCA1/2 testing one or more years ago also reported fewer positive experiences 1 week after receiving results.

Conclusions: Together, these findings demonstrate that a sizable minority of patients have important concerns regarding multiplex tests that may limit their uptake of this novel testing, and suggest that some patients may prefer to customize the specific risk information provided. Results also highlight characteristics of those at risk for poorer emotional outcomes following testing; these individuals may benefit from additional support in this context.

Citation Format: Robson ME, Gaissert P, Salo-Mullen EE, Amoroso K, Sheehan M, Berliner JL, Trottier M, Arnold AG, Sekhri N, Marcell V, Siegel B, Harlan Fleischut M, Hay JL, Walsh MF, Kauff ND, Stadler ZK, Offit K, Hamilton JG. Information preferences and short-term psychological responses to multiplex genetic testing among individuals at risk for hereditary breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-09-24.

Decision Making about Contralateral Prophylactic Mastectomy Among BRCA1/2 Noncarriers with Newly-diagnosed Breast Cancer: Examining Cognitive, Emotional, and Sociodemographic Influences

Pre-surgical BRCA1/2 genetic testing provides valuable risk information to guide a newly-diagnosed breast cancer patient's decision about whether to have a contralateral prophylactic mastectomy (CPM) to reduce her future risk of cancer in her unaffected breast. Although BRCA1/2 mutation noncarriers face a much lower objective ten-year risk of developing contralateral disease (approximately 3–10%) as compared to the risk of BRCA1/2 mutation carriers (27–37%), some noncarriers still choose to undergo a CPM. The psychosocial factors that motivate this decision are not well understood and warrant investigation. Thus, as part of a prospective study of pre-surgical BRCA1/2 testing, we examined the frequency and psychosocial correlates of the decision to undergo a CPM among newly-diagnosed breast cancer patients who were identified as BRCA1/2 mutation noncarriers. Self-report questionnaire data from 90 BRCA1/2 noncarriers (median age = 43 years, range = 29–59) were analyzed. A sizeable minority of the BRCA1/2 noncarriers (24.4%) chose to undergo a CPM after learning their mutation status (compared to 88% of the 8 BRCA1/2 carriers in the sample). Both bivariate and multivariable analyses indicated that perceiving that one's physician had recommended CPM (OR = 11.17, P = 0.007), perceiving greater risk for contralateral breast cancer (OR = 6.46, P = 0.02), and perceiving greater pros of CPM (OR = 1.37, P = 0.004) were all significantly associated with noncarriers' decision to undergo CPM. However, factors including age, Ashkenazi Jewish ethnicity, breast cancer-related distress, perceived cons of CPM, and decisional conflict regarding CPM were not related to the CPM decision (all ps > 0.05). Results demonstrate that although noncarriers' decision making regarding CPM was unrelated to sociodemographic and emotional factors, their cognitive perceptions of contralateral disease risk, surgical benefits, and physician recommendations were particularly important. Future studies should examine the content of patient-physician communication regarding CPM and hereditary risk in greater detail, and explore how these conversations shape and interact with women's past experiences, emotions, and beliefs to influence their cancer prevention decisions.

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.

The role of pheromones in tick biology

Ticks are important vectors of pathogens that cause human and animal disease. Pheromones play a role of fundamental importance in intraspecies communication. Here, Gordon Hamilton discusses how these chemical messengers play a role in mate location, host location, and survival in adverse conditions, and how manipulation of this chemical communication system may provide a potential method of tick control.

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 (R_T ) between maintenance (R_M ), growth (R_G ), and N uptake respiration (R_N ) 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 R_G for loblolly pine in elevated CO₂ . Root specific R_M 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 R_N (< 3%) were small components of R_M in both forests. Maintenance respiration was the vast majority of R_T , 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 R_T and total soil CO₂ efflux, changes in R_M caused by warming may greatly alter carbon losses from forests to the atmosphere.

Impact of folivory on photosynthesis is greater than the sum of its holes

The effects of herbivores on plant production and fitness may not relate directly to the quantity of biomass removed because folivory may alter photosynthetic rates at a considerable distance from the damaged tissue [Welter, S. C. (1989) in Insect-Plant Interactions, ed. Bernays, E. A. (CRC, Boca Raton), pp. 135-151.]. An impediment to understanding the effects of leaf damage on photosynthesis has been an inability to map photosynthetic function within a single leaf. We developed an instrument for imaging chlorophyll fluorescence and used it to map the effects of caterpillar feeding on whole-leaf photosynthesis in wild parsnip. The adverse effects of caterpillar feeding on photosynthesis were found to extend well beyond the areas of the leaflet in which caterpillars removed tissue. These "indirectly" affected areas remained impaired for at least 3 days after the caterpillars were removed and were six times as large as the area directly damaged by the caterpillars. Although photosynthesis in indirectly affected areas was reduced and not eliminated, these areas accounted for three times as much of the overall reduction in photosynthesis as the area removed by the caterpillars. The size of the indirect effects was positively correlated with defense-related synthesis of furanocoumarins, suggesting that costs of chemical defense may be one factor that accounts for the indirect effects of herbivory on plants.

Sugars in the gut of the sandfly Phlebotomus orientalis from Dinder National Park, Eastern Sudan

The sandfly Phlebotomus orientalis Parrot (Diptera: Psychodidae) is the vector of visceral leishmaniasis in eastern and Upper Nile regions of Sudan, where vector infection rates of over 7% have been reported. Sugars are known to be important for development of the parasite and for increasing the survival and oviposition rates of several species of sandflies. In the present study we have analysed the sugars present in the guts of individuals and groups of male and female P. orientalis and compared these with sugars from several potential local plant sources: Acacia seyal, Balanites aegyptiaca and Combretum kordofanum. The distribution of these trees in Sudan is closely correlated with that of P. orientalis. Only 20% of individually analysed female sandflies had significant amounts of sugars present suggesting that P. orientalis either digest their sugar meal quickly or do not require regular sugar meals. Interestingly, the sugars present in the males were significantly different to those found in the females, indicating that they had fed on different sugar sources. There was evidence that fruit sugars from Balanites aegyptiaca, Combretum kordofanum and aphid or coccid honeydew are utilized by male and female P. orientalis. There was evidence to indicate that female P. orientalis feeds directly on honeydew. There was no evidence to indicate that direct feeding on leaves is a typical source for the sugar meal. There was no melizitose and only a very small amount of turanose present in the male, suggesting that honeydew was not an important sugar source for males.

Net primary production of a forest ecosystem with experimental CO2 enrichment

The concentration of atmospheric carbon dioxide was increased by 200 microliters per liter in a forest plantation, where competition between organisms, resource limitations, and environmental stresses may modulate biotic responses. After 2 years the growth rate of the dominant pine trees increased by about 26 percent relative to trees under ambient conditions. Carbon dioxide enrichment also increased litterfall and fine-root increment. These changes increased the total net primary production by 25 percent. Such an increase in forest net primary production globally would fix about 50 percent of the anthropogenic carbon dioxide projected to be released into the atmosphere in the year 2050. The response of this young, rapidly growing forest to carbon dioxide may represent the upper limit for forest carbon sequestration.

Comparison of the sex-pheromone components of Lutzomyia longipalpis (Diptera:Psychodidae) from areas of visceral and atypical cutaneous leishmaniasis in Honduras and Cost Rica

The terpene components of extracts prepared from male Lutzomyia longipalpis (Diptera: Psychodidae) collected from four sites in Honduras and one in Costa Rica were analysed by high-performance liquid chromatography, gas chromatography and coupled gas chromatography--mass spectrometry. The terpene components of Lu. longipalpis from other regions of South America have previously been shown to be sex pheromones. The flies from the four areas of Honduras, where Leishmania chagasi infection may lead to visceral or atypical cutaneous leishmaniasis, were found to be homogenous, all producing 9-methylgermacrene-B. Three types of terpene (9-methylgermacrene-B, a novel homosesquiterpene and a small amount of diterpene) were detected in pools of flies from Liberia, Costa Rica, where only atypical cutaneous leishmaniasis has been found. These results indicate that there are probably at least two and possibly three distinct populations of Lu. longipalpis in this region. The clinical manifestation of Leishmania chagasi infection does not appear to be dependent on which population of Lu. longipalpis transmitted the parasite.

Spectral sensitivity in the eyes of male and female Lutzomyia longipalpis sandflies

Using electroretinogram recordings, the response of Lutzomyia longipalpis sandfly eyes to a range of wavelengths of light was measured, and spectral sensitivity determined. The eyes of both male and female adult sandflies were found to respond maximally to light in the ultraviolet region (at 340 nm) with a secondary peak in the blue-green-yellow region at 520 nm for females and 546 nm for males. The Mann-Whitney U test showed no significant differences between males and females at corresponding wavelengths.

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.

Needle phobia: a neglected diagnosis

Needle phobia is a recently defined medical condition that affects at least 10% of the population. Because persons with needle phobia typically avoid medical care, this condition is a significant impediment in the health care system. The etiology of needle phobia lies in an inherited vasovagal reflex of shock, triggered by needle puncture. Those who inherit this reflex often learn to fear needles through successive needle exposure. Needle phobia is therefore both inherited and learned. In a family practice, needle phobia can be managed by reassurance and education, avoidance of needles, postural and muscle tension techniques, benzodiazepines, nitrous oxide gas, and topical anesthesia applied by iontophoresis.

The effect of female body size on male mounting behaviour in Dermacentor variabilis and D. andersoni

This study was undertaken to determine if body size of female ticks was an important factor in eliciting the mating behaviour of Dermacentor variabilis and D. andersoni males. Dummy female ticks (DFTs) representing varying sizes of feeding females were prepared from plastic beads. Size of DFT was shown to be important in determining both the time spent by males in contact with DFTs and the extent of male mating response released. Dermacentor variabilis males preferred the smaller-sized DFT, whereas D.andersoni males preferred the larger sizes. Males of both species were able to discriminate between size of DFT only when mounting sex pheromone (MSP) was present. Size of the DFT was more important than the composition of the MSP extract in determining the time males spent in contact with DFTs. Males of both species were sensitive to variations in concentration of extract, and spent 2-6 times longer in contact with DFTs when the concentration was optimal than when it was not. No significant difference in the male's mating response was seen in response to variation in concentration of heterospecific extract. Male mating response, i.e. the behaviour of the male as it progresses through the initial contact, climbing onto the dorsal surface and turning onto the venter, was shown not to be dependent upon how long the male spent in contact with the DFT. Male D. andersoni had a much lower mating response to DFTs than D. variabilis males, suggesting that some further stimulus may be required.

Purification and characterization of an acyclic monoterpene primary alcohol:NADP+ oxidoreductase from catmint (Nepeta racemosa)

A soluble monoterpene primary alcohol:NADP+ oxidoreductase has been purified to apparent homogeneity from leaves of the catmint, Nepeta racemosa. The purified enzyme consisted of two polypeptides, with molecular masses of 42,000 and 40,000 Da, and contained zinc ions. A number of monoterpene alcohols (geraniol, nerol, citronellol, and their hydroxylated derivatives) were substrates, but the enzyme was inactive toward ethanol. The enzyme required NADP(H) as cofactor, with NAD(H) ineffective. Gas chromatographic and coupled mass spectrometric analysis of the reaction products showed that 10-hydroxygeraniol and 10-hydroxynerol were oxidized by the enzyme in the presence of NADP+, at both C-1 and C-10. These results are consistent with a role for this enzyme in the biosynthesis of iridoid monoterpenes.

Attraction of Lutzomyia longipalpis to human skin odours

Male and female Lutzomyia longipalpis sandfiles showed attraction to human skin emanations placed on warmed glass Petri dishes. Unfed virgin females were more strongly attracted than males, which also showed attraction. Four human subjects were tested and significant variation was found between the numbers of sandflies attracted to their skin emanations. This suggests that some individuals were more attractive than others. There was a significant difference between the response shown by sandflies from the Jacobina and Lapinha regions of Brazil, suggesting that sandflies from the Jacobina region were more anthropophilic. In addition, sandflies from Jacobina had a significantly higher level of activity than those from Lapinha. The role of sandfly attraction to humans as a risk factor in Leishmania transmission is considered.

Chemical analysis of a putative sex pheromone from Lutzomyia pessoai (Diptera: Psychodidae)

Lutzomyia pessoai has been named as a probable vector of Leishmania braziliensis in southern Brazil. Males of this species have recently been shown to have pheromone-disseminating structures on their abdomen. Chemical analysis of extracts from the glands associated with these structures has revealed the presence of a possible sex pheromone. Although this compound has been partially characterized as a monocyclic diterpene with the same molecular weight as the Lu. longipalpis diterpene sex pheromone, mass spectral evidence indicates that it is different compound. This, the first evidence for a possible sex pheromone in any phlebotomine species other than Lu. longipalpis, indicates that such semiochemicals may be widely distributed in this group.

Evidence for a mounting sex pheromone in the brown ear tick Rhipicephalus appendiculatus, Neuman 1901 (Acari: Ixodidae)

The presence of a mounting sex pheromone was demonstrated on the surface of fed female Rhipicephalus appeniculatus. This pheromone, which is present on the female cuticle, allows the male to recognise the female. The pheromone was removed by cleaning the female in hexane, resulting in the loss of male mating behaviour in in vitro experiments. Male mating behaviour was resumed when extract made from fed female cuticle was replaced on cleaned females. When the extract was transferred to inanimate objects typical male mating behaviour was released. Preliminary chemical analyses indicated that the active component of the extract was contained in the sterol ester fraction of the extract.

Isolation of oviposition pheromone from the eggs of the sandfly Lutzomyia longipalpis

Semiochemical components of eggs of the sandfly Lutzomyia longipalpis (Diptera: Psychodidae) were separated by high performance liquid chromatography. HPLC fractions were examined quantitatively and qualitatively by gas chromatography (GC). A bioassay was used to determine the oviposition attraction of gravid L. longipalpis to each of the fractions separately and a peak responsible for the semiochemical activity was identified. Gravid flies were placed in individual oviposition tubes to determine if the peak of interest was an oviposition stimulant. The active semiochemical fraction attracted gravid flies for oviposition. Furthermore, egg laying was enhanced: gravid flies exposed to the pheromone oviposited earlier and laid more eggs than control flies. GC analysis indicated that 1200 eggs (2 days old) gave a yield of 12.75 micrograms of active pheromone. This fraction had similar HPLC and GC retention times to caryophyllene oxide, suggesting comparable polarity and molecular weight.

Semiochemical mediation of oviposition by the phlebotomine sandfly Lutzomyia longipalpis

Extracts of rabbit food, hay and rabbit faeces elicited a positive oviposition response from gravid female Lutzomyia longipalpis sandflies (Diptera: Phlebotominae). Combined extract of rabbit food and oviposition pheromone had a synergistic effect on sandfly egg-laying, greatly increasing the number of eggs laid and resulting in a highly targeted response. Individually tubed flies, exposed to the combined extract, were shown to be 3.5 times more likely to survive oviposition and laid 2.5 times more eggs than control flies. A laboratory oviposition trap baited with the combined extract was tested in a cage and caught 31 (62%) of 50 gravid L. longipalpis over a 72h period.

Gas-chromatographic analysis of Lutzomyia longipalpis tergal pheromone gland extract

Lutzomyia longipalpis is the vector of visceral leishmaniasis (VL) in South America. Previous gas-chromatographic (GC) analyses of tergal gland extracts of Lu. longipalpis have demonstrated two distinct pheromone types. These have been classified as a farnesene/homofarnesene type compound and a diterpene type compound. GC analysis of tergal gland extracts of Lu. longipalpis from other areas of South America demonstrates that there may be other different pheromone producing forms of this sandfly. Gland extracts are more complex than has previously been indicated, and they have been shown to differ in the chemicals present and in the ratio of these compounds to each other.

Effect of Temperature on Development Rate, Survival and Fecundity of Cotton Tipworm, Crocidosema-Plebejana Zeller (Lepidoptera, Tortricidae)

C. plebejana were reared from egg to adult at a range of constant temperatures. At 10-degrees-C no immature stages survived. Development rates increased over the temperature range 14-34-degrees-C; these were simulated with a non-linear model. Females emerged before males. Fecundity decreased with increased rearing temperature as a direct result of reduced adult female weight. At 34-degrees-C development rate and survival were reduced and all eggs laid were infertile. Optimum temperature for population increase was 28-degrees-C. Validation of a non-linear model for development rate shows that the species of host-plant affects mean development rates of tipworm. Although 5.3 tipworm generations are possible on cotton annually, only one occurs; reasons for this are suggested.

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%.

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%.

Congenital dermal sinus presenting as anaerobic meningitis

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Multichemical defense of plant bugHotea gambiae (westwood) (Heteroptera: Scutelleridae) : Sesquiterpenoids from abdominal gland in larvae

Chemical defense in larvae of the plant bugHotea gambiae has been investigated. Results of analyses (GC, GC-MS) on the secretions from the three dorsally situated larval abdominal defense (scent) glands are reported. The secretion from the first abdominal gland consists of a mixture of C10 and C15 isoprenoids: (C10) α-pinene, β-pinene, limonene, β-phellandrene; (C15) β-caryophyllene, caryophyllene oxide, α-humulene, and (the major component) humulene epoxide II. The secretions from the second and third abdominal glands are similar mixtures consisting of (E)-2-decenal, (E)-4-oxohex-2-enal, andn-tridecane together with lesser amounts of (E)-2-hexenal,n-dodecane, and other materials. Isoprenoid defense is now known from four species of plant bugs (Heteroptera) associated with Malvaceae.

Separation of neutral lipids and free fatty acids by high-performance liquid chromatography using low wavelength ultraviolet detection

Normal phase, isocratic high-performance liquid chromatography methods are described for the separation of neutral lipid and fatty acid classes using low wavelength detection. Prior to high-performance liquid chromatography, methods were developed and are described for the separation of phospholipids from neutral lipids and fatty acids using small (600 mg) silica Sep-PaksTM. Recoveries of cholesteryl esters, triglycerides, fatty acids, and phospholipids from the silica columns were greater than 95%. Two mobile phases are described for lipid class separation by high-performance liquid chromatography. The first mobile phase, hexane-2-propanol-acetic acid 100:0.5:01, resulted in incomplete separation of cholesteryl ester and triglyceride but excellent separations of fatty acids and cholesterol. The second mobile phase, hexane-n-butyl chloride-acetonitrile-acetic acid 90:10:1.5:0.01, resulted in complete separation of the four lipid classes. This mobile phase also separated individual triglycerides and fatty acids based on the number of double bonds. Recoveries of radiolabeled lipids for the four lipid classes from high-performance liquid chromatography was greater than 95% with both mobile phases.

Intracranial haemorrhage in association with pseudoephedrine overdose

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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.

Determination of xylitol in human urine by gas-liquid chromatography

A rapid and specific method for the quantitative determination of xylitol in human urine has been developed. The method consists of the gas-liquid chromatographic analysis of the acetate ester derivative of the alditol in deionized urine using dulcitol as an internal standard. As little as 20 ng xylitol can be detected. At concentrations ranging from 25 to 400 micrograms/ml urine, the accuracy is +/- 4.0%.

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.