Ovarian maturation in stable flies: inhibition by 20-hydroxyecdysone.

The steroid 20-hydroxyeedysone when given by mouth inhibits ovarian maturation in the stable fly, Stomoxys calcitrans (L.). by preventing lipid synthesis flecessary foir vitellogenlesis in the developing oocyte.

Myristicin in cigarette smoke.

The pharmacologically active aromatic ether, myristicin, was isolated from the smoke of commercial cigarettes. The compound was identified by spectrometry (infrared, ultraviolet, and mass) and gas chromatography. The amount of myristicin in smoke is relatively low, and its contribution, if any, to the physiological action of cigarette smoke is unknowvn.

Stability in shifting sands: contemporary leadership roles in critical care.

BACKGROUND: Contemporary nursing leadership roles in critical care are a reflection of the changing environment in which critical care is provided. KEY ISSUES: In the UK, critical care nursing faces challenges in the form of: reduced number and seniority of medical staff cover for acute wards; mandated responsibility for management of patients outside of critical care units, without corresponding responsibility for managing staff; increased public and political awareness of deficits in critical care; increased use of Assistant Practitioners; and emphasis on longer-term outcomes from intensive care. EVALUATION: New leadership roles have met these challenges head on with two main foci: patient management across the acute/critical care interface and hospital wide policies and practice. CONCLUSIONS: The leadership roles examined in this paper highlight three underpinning goals: improved quality and safety of patient care; improved communication between professionals; and empowerment of junior nurses and doctors. IMPLICATIONS FOR NURSING MANAGEMENT: There has been considerable investment in strategic leadership roles for critical care nursing; evidence is developing of the return on this investment for patient and service outcomes. Consideration must now be given to the preparation, mentorship and development of leadership roles for the next generation of nurse leaders.

Mouse skin tumorigenesis and induction of aryl hydrocarbon hydroxylase by tobacco smoke fractions.

Ten fractions separated from the neutral portion of cigarette smoke condensate (CSC) were tested on mouse skin for tumor-initiating activity and for their capacity to induce the enzyme aryl hydrocarbon hydroxylase (AHH). Tumor-initiating activity was confined primarily to the fraction containing more than 90% of the polynuclear aromatic hydrocarbons (PAH) in CSC. One other PAH-containing fraction was active. The combined initiating effect of these fractions was comparable to that of a 40-ppm solution of benzo[a]pyrene (BP), which is about 40 times the BP content of CSC. Some of the neutral fractions that have been demonstrated to cause tumor promotion in mice pretreated with 7,12-dimethylbenz-[aA1ANTHRACENE sere inactive as tumor initiators. The fractions that contained aromatic hydrocarbons induced mouse skin AHH levels twofold to sixfold after a single topical application. AHH-inducing activity was not, however, a reliable indicator of the carcinogenic potential of a fraction.

Identification of polynuclear aromatic hydrocarbons in cigarette smoke and their importance as tumorigens.

Fraction F20, which in other studies was the most tumorigenic neutral fraction of cigarette smoke condensate (CSC), was separated by gel filtration chromatography into refined subfractions for identification of the polynuclear aromatic hydrocarbons (PAH) and for bioassay on mouse skin. Several hundred PAH were positively identified. Subfraction F55. containing most of the carcinogenic PAH as well as numerous unidentified components, was almost as tumorigenic to 7,12-dimethylbenze[a]anthracene (DMBA)-pretreated female outbred CD-1 mice as was F20. When F55 was separated into two parts, the first containing unidentified material (F55A) and the second containing the PAH (F55B), neither was significantly tumorigenic. F55B, combined with two other active fractions from the neutral and the acidic portions of CSC, exhibited a synergistic tumorigenic effect on DMBA-pretreated mice. The results supported the concept that the PAH in cigarette smoke must interact with other components in order to exert a tumorigenic effect.

Perceptions of a good death: A qualitative study in intensive care units in England and Israel.

OBJECTIVES: To explore factors perceived to contribute to 'a good death' and the quality of end of life care in two countries with differing legal and cultural contexts. DESIGN AND METHODS: Multi-centre study consisting of focus group and individual interviews with intensive care nurses. Data were analysed using qualitative thematic analysis; emotional content was analysed using specialist linguistic software. SETTINGS/PARTICIPANTS: Fifty five Registered Nurses in intensive care units in Israel (n=4) and England (n=3), purposively sampled across age, ICU experience and seniority. FINDINGS: Four themes and eleven sub-themes were identified that were similar in both countries. Participants identified themes of: (i) timing of communication, (ii) accommodating individual behaviours, (iii) appropriate care environment and (iv) achieving closure, which they perceive prevent, and contribute to, a good death and good quality of end of life care. Emotional content showed significant amount of 'sadness talk' and 'discrepancy talk', using words such as 'could and 'should' when participants were talking about the actions of clinicians. CONCLUSIONS: The qualities of a good death were more similar than different across cultures and legal systems. Themes identified by participants may provide a framework for guiding end of life discussions in the intensive care unit.

Transcription of the FMR1 gene in individuals with fragile X syndrome.

Fragile X syndrome generally arises as a consequence of a large expansion of a CGG trinucleotide repeat element that is located in the GC-rich promoter region of the fragile X mental retardation gene (FMR1). In the conventional model for fragile X, clinical involvement arises as a consequence of silencing of the FMR1 gene, with the attendant loss of FMR1 protein (FMRP). However, it has recently been demonstrated that most males with large premutation alleles (100-200 repeats), or with unmethylated full mutation alleles, have FMR1 mRNA levels that are higher than normal, despite reduced levels of FMRP. In the current work, we extend and confirm these observations using quantitative (fluorescent) reverse transcription polymerase chain reaction on larger sample populations, establishing that even for smaller premutation alleles (55-100 repeats) the mRNA levels are significantly elevated (mean 2.1-fold elevation; P = 3.9 x 10(-3)), relative to normal controls. Thus, an abnormal molecular phenotype is established close to the upper end of the normal range. We also demonstrate that the levels of FMR1 mRNA are elevated in females with premutation alleles; however, the mRNA levels are more varied than in the males, and are attenuated in a manner that is consistent with the fraction of normal alleles that are active in any given individual. Finally, we demonstrate that in lymphoblastoid cells derived from a patient with a severe form of fragile X caused by a point mutation in the second KH domain of the gene, but with a normal CGG element (25 repeats), the FMR1 mRNA level is normal. Thus, although models in which FMRP level (or level of function) modulates transcriptional activity remain viable, other explanations for the elevated message levels, including direct (cis) effects of the CGG element on transcription, must also be considered.

Selenium-mediated reduction in the mutagenicity of cigarette smoke.

Cigarette smoke contains carcinogens and mutagens and affects the health of smokers. Recently, increased research has proven the potentially protective activity of selenium (Se) against heavy metal toxicity, cancer, and other health disorders. Accordingly, we have proposed the fortification of tobacco with Se to develop safer cigarettes. As a start in evaluating any biological effects of added Se, we have determined the mutagenicity of inhaled, mainstream (MS) cigarette smoke condensate (CSC), with and without Se, in the preincubation assay of the Ames test. Initially, it was shown that Se, as sodium selenite, was not mutagenic at high concentrations (up to 80 micrograms/plate) with strains TA1538 and TA1978. Subsequently, the effects of different levels of Se, added to MS CSC, were examined with TA98, TA100, and TA1538. On the average, addition of 10 micrograms Se produced mutagenicity reductions of about 50%. Higher levels of added Se yielded further reductions. Cigarette sidestream (SS) smoke, collected between puffs, was also tested. Again, Se added to SS-CSC gave similar reductions, confirming its antimutagenic effect for both mainstream and sidestream smoke.

Pyridostigmine-induced decrement in skeletal muscle contracture is not augmented by soman.

Previous studies have reported that pyridostigmine induces a decrement in contractile force generated during tetanic stimulation of skeletal muscle. Although our studies suggested that pyridostigmine affected release of transmitter from the motor nerve terminal, we could not exclude the possibility that the drug's action was due to depolarization blockade of the muscle brought on by excessive transmitter in the synaptic cleft. The purpose of this study was to determine whether the effect of combined treatment with pyridostigmine and an irreversible cholinesterase inhibitor (soman) would potentiate the decrement in muscle contracture observed with pyridostigmine alone. As reported previously, pyridostigmine (25 mg/kg) significantly reduced muscle contracture during tetanic stimulation (20-100 Hz), and soman (0.075 mg/kg) increased muscle contracture. Combined treatment with pyridostigmine and soman produced a decrease in muscle contracture equivalent to the effect of pyridostigmine alone. Since there was no evidence of depolarization blockade of the muscle despite aggressive treatment with two cholinesterase inhibitors, these results support the view that pyridostigmine has a significant presynaptic action to decrease neurotransmitter release. This action opposes the drug's inhibition of cholinesterase, and the net effect of combined treatment with pyridostigmine and soman is a muscle response which is largely unchanged from the effect of pyridostigmine alone.

New procedures to enhance survival of third-instar Hypoderma lineatum (Villers) (Diptera: Oestridae) in artificial media.

New techniques for the maturation of late third instars of the common cattle grub, Hypoderma lineatum (Villers), in artificial media are described. Larvae were held in either 24-well culture plates with media plus penicillin, streptomycin sulfate, nystatin, and chloramphenicol or in small salve jars on Perlite and media plus the same antibiotics. Chloramphenicol was not always necessary in the jars. Survival to pupariation of young third instars increased from 5% without nystatin and chloramphenicol to 73% when the two antibiotics were present in the culture plates. The survival of mature third instats to pupariation increased from approximately 53 to 80% after addition of nystati and chloramphenicol to the culture plates. Survival to pupariation of more mature grubs was similar in the jar and culture plate techniques. The former was more convenient, but the young grubs did not survive well in the jars.

Technique for age-grading late third-instar Hypoderma lineatum (Diptera: Oestridae).

Three developmental phases are described for age-grading third-instar Hypoderma lineatum (Villers) based on color and development of the posterior spiracles. Early Phase 1 (P1) larvae are white in appearance, and their kidney-shaped posterior spiracular plates have no melanization. By the end of this phase, the cuticle has become yellow, and the margins of the spiracular plates begin to melanize. The cuticle of P2 larvae continues darkening from yellow to tan to light brown and is accompanied by a progressive melanization of the spiracular plates. The third phase, P3, has a cuticle that is not black like larvae that are ready to emerge from the hides for pupation, but the posterior spiracular plates are fully developed and melanized without a space between the two plates.

Levels of fumonisin B1 in corn naturally contaminated with aflatoxins.

Aflatoxins and fumonisin B1 are hepatotoxic and carcinogenic metabolites produced by Aspergillus flavus and Fusarium moniliforme, respectively. These fungi are common natural contaminants of corn, and both aflatoxins and fumonisin B1 have been implicated as aetiological agents in animal and human diseases. To determine whether these mycotoxins co-exist on corn under natural conditions, 28 samples from the 1991 Georgia (USA) corn crop were assayed for (total) aflatoxin and fumonisin B1. 27 samples were positive for aflatoxin, 24 samples were positive for fumonisin B1, and 23 samples had detectable levels of both. In the positive samples, the mean aflatoxin concentration was 73 ppb (SD = 86), and the average fumonisin B1 concentration was 0.87 ppm (SD = 0.65). A correlation between aflatoxin and fumonisin B1 concentrations was not evident. None the less, these results demonstrate that exposure to both mycotoxins can occur simultaneously by consumption of co-contaminated corn.

Azadirachtin as a larvicide against the horn fly, stable fly, and house fly (Diptera: Muscidae).

Effects of azadirachtin, a triterpenoid extracted from neem seed, Azadirachta indica A. Juss., were similar to those of insect growth regulators against the immature stages of the born fly, Haematobia irritans (L.), the stable fly, Stomoxys calcitrans (L.), and the house fly, Musca domestica L. When an ethanolic extract of ground seed was blended into cow manure, LC50 and LC90's for larval horn flies were 0.096 and 0.133 ppm azadirachtin, respectively. An emulsifiable concentrate (EC) had an LC50 for larval horn flies of 0.151 ppm and an LC90 of 0.268 ppm. For larval stable flies, the EC formulation had an LC50 of 7.7 ppm and an LC90 of 18.7 ppm azadirachtin in manure. Against larval house flies, the LC50 and LC90 were 10.5 and 20.2 ppm, respectively. When the EC formulation was administered orally to cattle at a rate of greater than or equal to 0.03 mg azadirachtin per kg of body weight per day or when ground neem seed was given as a daily supplement of greater than or equal to 10 mg seed per kg body weight, horn fly development in the manure was almost completely inhibited. In contrast, ground seed mixed in cattle feed at the rate of 100-400 mg seed per kg of body weight per day caused less than 50% inhibition of stable flies in the manure.

The application of solid phase extraction to the analysis of tobacco-specific nitrosamines.

A new isolation and separation method has been developed for the alkaloid-related nitrosamines in tobacco, called tobacco-specific nitrosamines (TSNA). The improved isolation procedure involves the extraction by sonication of TSNA from cured tobacco with toluene and an aqueous citrate buffer solution, while purification is achieved by solid phase extraction on small silica cartridges. Interfering extract materials are eluted from the silica cartridges with the toluene and a chloroform-methylene chloride solvent, while subsequent elution with chloroform yields the TSNA in a purified fraction. Gas chromatographic analyses on an SE-54-coated glass capillary column and detection by a nitrogen-phosphorous detector produce very good data on the four TSNAs, which include N-nitrosanatabine (NATB), N-nitrosoanabasine (NAB), 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (called NNK), and N-nitrosonornicotine (NNN). The method is shown to be quantitative, reproducible, and applicable to the determination of TSNA in various tobacco samples, such as stems and lamina of cured tobacco leaves, as well as to smokeless tobacco.

A study on the mutagenicity of tobacco smoke from low-tar cigarettes.

A series of 16 low-tar cigarettes, yielding from 1 to 10 mg of tar, were smoked on a modified cigarette smoking machine that collected both mainstream (MS, inhaled) smoke and sidestream (SS, between puffs) smoke. The SS smoke is the major contributor to environmental tobacco smoke. The collected MS and SS smoke condensates were evaluated for mutagenicity by the Ames test and compared with MS and SS smoke condensates from a high-tar cigarette. Both MS and SS condensates of low-tar cigarettes (LTCs) were tested with the Salmonella strains TA1538 and TA100. Except for three cigarettes, the MS smoke mutagenicities of the LTC smoke condensates were significantly reduced (about 30%) when compared with a control, high-tar (23-mg) cigarette. Opposite results were obtained for the SS smoke condensates, which were more mutagenic (about 20%) than the SS smoke condensate of the high-tar cigarette. Thus, LTC mainstream smoke may be less hazardous to the LTC smoker, whereas LTC sidestream may emit more mutagenic compounds into environmental tobacco smoke, which, through passive inhalation, could affect both smokers and nonsmokers.