Evolution of apomixis loci in Pilosella and Hieracium (Asteraceae) inferred from the conservation of apomixis-linked markers in natural and experimental populations.

The Hieracium and Pilosella (Lactuceae, Asteraceae) genera of closely related hawkweeds contain species with two different modes of gametophytic apomixis (asexual seed formation). Both genera contain polyploid species, and in wild populations, sexual and apomictic species co-exist. Apomixis is known to co-exist with sexuality in apomictic Pilosella individuals, however, apomictic Hieracium have been regarded as obligate apomicts. Here, a developmental analysis of apomixis within 16 Hieracium species revealed meiosis and megaspore tetrad formation in 1 to 7% of ovules, for the first time indicating residual sexuality in this genus. Molecular markers linked to the two independent, dominant loci LOSS OF APOMEIOSIS (LOA) and LOSS OF PARTHENOGENESIS (LOP) controlling apomixis in Pilosella piloselloides subsp. praealta were screened across 20 phenotyped Hieracium individuals from natural populations, and 65 phenotyped Pilosella individuals from natural and experimental cross populations, to examine their conservation, inheritance and association with reproductive modes. All of the tested LOA and LOP-linked markers were absent in the 20 Hieracium samples irrespective of their reproductive mode. Within Pilosella, LOA and LOP-linked markers were essentially absent within the sexual plants, although they were not conserved in all apomictic individuals. Both loci appeared to be inherited independently, and evidence for additional genetic factors influencing quantitative expression of LOA and LOP was obtained. Collectively, these data suggest independent evolution of apomixis in Hieracium and Pilosella and are discussed with respect to current knowledge of the evolution of apomixis.

Genetic map construction and QTL mapping of resistance to blackleg (Leptosphaeria maculans) disease in Australian canola (Brassica napus L.) cultivars.

Genetic map construction and identification of quantitative trait loci (QTLs) for blackleg resistance were performed for four mapping populations derived from five different canola source cultivars. Three of the populations were generated from crosses between single genotypes from the blackleg-resistant cultivars Caiman, Camberra and (AV)Sapphire and the blackleg-susceptible cultivar Westar(10). The fourth population was derived from a cross between genotypes from two blackleg resistant varieties (Rainbow and (AV)Sapphire). Different types of DNA-based markers were designed and characterised from a collection of 20,000 EST sequences generated from multiple Brassica species, including a new set of 445 EST-SSR markers of high value to the international community. Multiple molecular genetic marker systems were used to construct linkage maps with locus numbers varying between 219 and 468, and coverage ranging from 1173 to 1800 cM. The proportion of polymorphic markers assigned to map locations varied from 70 to 89% across the four populations. Publicly available simple sequence repeat markers were used to assign linkage groups to reference nomenclature, and a sub-set of mapped markers were also screened on the Tapidor x Ningyou (T x N) reference population to assist this process. QTL analysis was performed based on percentage survival at low and high disease pressure sites. Multiple QTLs were identified across the four mapping populations, accounting for 13-33% of phenotypic variance (V (p)). QTL-linked marker data are suitable for implementation in breeding for disease resistance in Australian canola cultivars. However, the likelihood of shifts in pathogen race structure across different geographical locations may have implications for the long-term durability of such associations.

A profile of perianesthesia nursing patient outcome research, 1994-1999.

The purpose of this research was to profile the current body of perianesthesia nursing research and extend the findings of previous integrative reviews completed on research from 1982 to 1993. The tables of contents from 18 nursing journals were examined and 31 studies met inclusion criteria. Findings indicated that some improvements were made by perianesthesia nurse researchers in using the scientific method. No studies replicated previously published research before 1994. Pediatric and elderly studies were scarce. Free-standing ambulatory surgery continues to be an under-represented research setting.

The impact of supplemental feeding in young children on dialysis: a report of the North American Pediatric Renal Transplant Cooperative Study.

Supplemental feedings are commonly recommended for young children on dialysis but their effect on growth parameters and mortality has not been well documented. We report the results of a North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) survey on the impact of supplemental feedings on growth and mortality in children < 6 years of age at dialysis initiation. Sixty-four nonsurvivors (NonS) were matched with 110 survivors (S) for age at dialysis initiation, primary renal disease, and year of entry into the NAPRTCS database. Questionnaires were completed by participating centers on 137 patients (51 NonS, 86 S). Supplemental feedings were given to 70% of patients and more commonly given to patients < 2 years of age compared to those 2-5 years of age at dialysis initiation (P < 0.001). Supplemental feedings were also more commonly given to patients with nonrenal disease in addition to renal disease compared to those with renal disease only (P < 0.001). In patients receiving supplemental feedings, the method of supplemental feeding was most commonly by nasogastric tube in patients < 2 years of age compared to those 2-5 years of age (P = 0.027). Supplemental feeding use was not different in S compared to NonS. There were no differences in height standard deviation score (SDS), weight SDS, or change in height or weight SDS in patients receiving supplemental feedings compared to those who did not. The height and weight SDS did not improve over time on supplemental feeds. In summary, despite the common use of supplemental feedings in young patients on dialysis, height, weight, and mortality remain unaffected. Prospective long-term evaluation of this therapy is needed to determine the effectiveness of supplemental feeding.

Risk factors for mortality in infants and young children on dialysis.

The factors associated with a greater mortality risk in infants and young children undergoing dialysis have not been clearly determined. We report the results of a North American Pediatric Renal Transplant Cooperative Study designed to assess risk factors in patients aged younger than 6 years at initiation of dialysis therapy. Sixty-four nonsurvivors were matched with 110 survivors for age at dialysis initiation, primary renal disease, and year of entry onto the database. Questionnaires on 137 patients (51 nonsurvivors, 86 survivors) were completed by participating centers. Seventy-five percent (103 of 137 patients) of the patients were aged younger than 2 years at dialysis initiation; 42% (58 of 137 patients) had renal aplasia, dysplasia, and/or hypoplasia or obstructive uropathy; 62% were boys; and 62% were white. One-year patient survival rates were 83% in infants beginning dialysis at younger than 3 months of age, 89% in 3- to 23-month-olds, and 95% in 2- to 5-year-olds (P = 0.001). Comorbid nonrenal disease occurred in 37 of 51 nonsurvivors (74%) versus 46 of 84 survivors (55%; P = 0.027). Nonsurvivors had pulmonary disease and/or hypoplasia more often (14 of 37 nonsurvivors; 37.8% versus 8 of 46 survivors; 17.4%; P = 0.04). Oliguria or anuria was present in 23 of 33 nonsurvivors (70%) aged younger than 2 years versus 26 of 64 survivors (41%; P = 0.007). Infection accounted for 15 of 51 deaths (29.4%). In summary, these results suggest that age at dialysis initiation; presence of nonrenal disease, particularly pulmonary disease and/or hypoplasia; and oliguria or anuria in children aged younger than 2 years are identifiable as risk factors for mortality in these young patients.

Reduced venous responsiveness to endothelin-1 but not noradrenaline in hypertensive chronic renal failure.

BACKGROUND: Endothelin-1 (ET-1), acting mainly through the ET(A) receptor, is a potent endothelium-derived vasoconstrictor peptide. Circulating concentrations of ET-1 are increased in chronic renal failure (CRF) and may influence vascular tone. METHODS: We investigated dorsal hand vein responsiveness to local infusion of ET-1 and noradrenaline in 12 hypertensive and 12 normotensive CRF patients and in 12 age and sex matched control subjects. We also investigated dorsal hand vein responses to the ET(A) receptor antagonist, BQ-123, and the endothelium-independent vasodilator glyceryl trinitrate (GTN), in six patients with CRF. RESULTS: The dose of noradrenaline causing a 50% of maximal vasoconstriction was similar in the hypertensive (32+/-11 pmol/min) and normotensive (26+/-7 pmol/min) CRF patients and control subjects (21+/-6 pmol/min). Vasoconstriction to ET-1 (5 pmol/min) was similar in CRF patients as a whole (AUC 35+/-5%) and controls (32+/-4%; P=0.70). However, venoconstriction was significantly less in hypertensive (23+/-6%) than in normotensive CRF patients (48+/-8%; P=0.01). Overall, venoconstriction to ET-1 correlated inversely with mean arterial blood pressure in the CRF patients (R=-0.43, P=0.04). In addition, basal vein size was smaller, and plasma endothelin concentrations greater, in the hypertensive CRF group. However, infusion of BQ-123 or GTN did not cause venodilatation in these subjects. CONCLUSIONS: These studies are consistent with the hypothesis that elevated plasma ET-1 contributes to vascular tone, and elevated blood pressure, in hypertensive CRF patients, and is associated with vascular receptor downregulation consequent on the increased exposure to ET-1. The reduced vein size in CRF patients appears to be structural rather than functional in nature. Further long-term studies with endothelin antagonists are required to determine the pathophysiological role of ET-1 in the altered structure and function of blood vessels in patients with CRF.

Reduction of skiing-related anterior shoulder dislocation using Kocher's method without traction.

We evaluated the use of Kocher's original method (without humeral traction) for reduction of acute anterior glenohumeral dislocation in 28 alpine skiers and snowboarders at a single ski area during the 1995-1996 ski season. In all cases, reduction was begun within 1 hour of the acute injury. The Kocher method alone was successful in 23 (82%) patients. Of the patients having a successful reduction by means of the original Kocher technique, the mean reduction time was less than 5 minutes, and 9 (39%) of the reductions were achieved in less than 1 minute. Only 1 patient experienced discomfort significant enough to require analgesia, and no patients required sedation. The complication rate was minimal, with 1 patient developing hyperesthesia in the axillary nerve distribution; no fractures of the humerus or glenoid resulted from the reduction technique.

Factors that influence personal perceptions of the risk of an acute myocardial infarction.

Personal risk perceptions of acute myocardial infarction (AMI) affect people's preventive health behaviors as well as their beliefs during a heart attack episode. The authors investigated factors that are associated with personal risk perceptions of having an AMI. A random-digit-dial survey was conducted among 1294 respondents, aged 18 years or older, in 20 communities across the nation as part of the Rapid Early Action for Coronary Treatment (REACT) trial. Results of two mixed-model linear regression analyses suggested that worse perceived general health, more risk factors, and greater knowledge were associated with greater perception of AMI risk. The results also showed that women who answered, incorrectly, that heart disease is not the most common cause of death for women in the United States reported significantly lower risk perceptions than women who answered this question correctly. The findings in this study suggest that interventions need to target specific misconceptions regarding AMI risk.

Effect of fish oil, arginine, and doxorubicin chemotherapy on remission and survival time for dogs with lymphoma: a double-blind, randomized placebo-controlled study.

BACKGROUND: Polyunsaturated n-3 fatty acids have been shown to inhibit the growth and metastasis of tumors. This double-blind, randomized study was designed to evaluate the hypothesis that polyunsaturated n-3 fatty acids can improve metabolic parameters, decrease chemical indices of inflammation, enhance quality of life, and extend disease free interval and survival time for dogs treated for lymphoblastic lymphoma with doxorubicin chemotherapy. METHODS: Thirty-two dogs with lymphoma were randomized to receive one of two diets supplemented with menhaden fish oil and arginine (experimental diet) or an otherwise identical diet supplemented with soybean oil (control diet). Diets were fed before and after remission was attained with up to five dosages of doxorubicin. Parameters examined included blood concentrations of glucose, lactic acid, and insulin in response to glucose and diet tolerance tests; alpha-1 acid glycoprotein; tumor necrosis factor; interleukin-6; body weight; amino acid profiles; resting energy expenditure; disease free interval (DFI); survival time (ST); and clinical performance scores. RESULTS: Dogs fed the experimental diet had significantly (P < 0.05) higher mean serum levels of the n-3 fatty acids docosahexaenoic acid (C22:6) and eicosapentaenoic acid (C20:5) compared with controls. Higher serum levels of C22:6 and C20:5 were associated with lesser (P < 0.05) plasma lactic acid responses to intravenous glucose and diet tolerance testing. Increasing C22:6 levels were significantly (P < 0.05) associated with longer DFI and ST for dogs with Stage III lymphoma fed the experimental diet. CONCLUSIONS: Fatty acids of the n-3 series normalize elevated blood lactic acid in a dose-dependent manner, resulting in an increase in DFI and ST for dogs with lymphoma.

The pharmacist's role in reducing patient delay in seeking treatment for acute myocardial infarction.

The most common reason for delay in treatment of an AMI is the patient's failure to seek care promptly. Individuals diagnosed with CHD, including those who have experienced an AMI, are considered to be at high risk for an AMI. These patients have the same or greater delay times as individuals without prior AMI or CHD. Pharmacists interact with these high-risk individuals and their families frequently in person or by telephone. During these interventions, they have the opportunity, through education and counseling, to improve their patients' understanding of early symptoms of AMI and the need for and benefits of prompt evaluation and treatment. Hearing this message from their pharmacist and from other health care providers in other settings will hopefully lead the high-risk individual to seek care promptly when needed. Successfully conveying this message could effectively reduce the morbidity and mortality associated with CHD.

Health care providers' perspectives on patient delay for seeking care for symptoms of acute myocardial infarction.

To inform intervention development in a multisite randomized community trial, the Rapid Early Action for Coronary Treatment (REACT) project formative research was undertaken for the purpose of investigating the knowledge, beliefs, perceptions, and usual practice of health care professionals. A total of 24 key informant interviews of cardiologists and emergency physicians and 15 focus groups (91 participants) were conducted in five major geographic regions: Northeast, Northwest, Southeast, Southwest, and Midwest. Transcript analyses revealed that clinicians are somewhat unaware of the empirical evidence related to the problem of patient delay, are concerned about the practice constraints they face, and would benefit from concrete suggestions about how to improve patient education and encourage fast action. Findings provide guidance for selection of educational strategies and messages for health providers as well as patients and the public.

Reducing patient delay in seeking treatment for acute myocardial infarction.

Although there have been tremendous strides in therapies for acute myocardial infarction (AMI), patients still do not receive these treatments in a timely manner, or sometimes not at all. One major reason is inadvertent delays by patients and by those with whom they consult about their symptoms. One of the National Heart Attack Alert Program's (NHAAP) goals is to reduce the morbidity and mortality associated with AMI through the rapid identification and treatment of at-risk individuals. Medical-surgical nurses can play a crucial role in ensuring that patients and their family members know how to recognize the signs and symptoms of a heart attack, what steps to take to get early and appropriate evaluation and treatment, and the potentially lifesaving benefits of this information.

Reduced endogenous endothelin-1-mediated vascular tone in chronic renal failure.

BACKGROUND: Endothelin-1 generated by the vascular endothelium contributes to basal vascular tone and blood pressure in healthy humans. Plasma concentrations of endothelin-1, which are elevated in chronic renal failure (CRF), may contribute to increased vascular tone. METHODS: We investigated the contribution of endogenous and exogenous endothelin-1 to the maintenance of vascular tone in patients with CRF (creatinine > or = 200 mumol/liter) and in age- and sex-matched healthy subjects. In a series of experiments, we measured forearm vascular responses to intra-arterial norepinephrine (30 to 240 pmol/min), endothelin-1 (5 pmol/min), the selective endothelin A (ETA) receptor antagonist BQ-123 (3 mg/hr), the mixed endothelin-converting enzyme and neutral endopeptidase inhibitor phosphoramidon (30 nmol/min), and the selective neutral endopeptidase inhibitor thiorphan (30 nmol/min). RESULTS: The maximum reduction in forearm blood flow (FBF) to norepinephrine in CRF (33 +/- 7%) was similar to that in controls (43 +/- 7%, P = 0.53). Endothelin-1 also produced a similar reduction in FBF in CRF (35 +/- 6%) and controls (36 +/- 5%, P = 0.81). BQ-123 increased FBF in CRF (11 +/- 4%) but significantly less than in controls (44 +/- 10%, P = 0.02). Phosphoramidon increased FBF in CRF (68 +/- 20%), again significantly less than in controls (181 +/- 41%, P = 0.001). Thiorphan reduced FBF similarly in CRF (22 +/- 6%) and controls (14 +/- 6%, P = 0.39). Responses to phosphoramidon were substantially greater than to BQ-123. CONCLUSIONS: These studies show that endogenous generation of endothelin-1 contributes to the maintenance of resting vascular tone in patients with CRF, as well as in healthy subjects. Although the contribution of endogenous endothelin-1 to resting vascular tone appears to be reduced in CRF, ETA receptor antagonism, and particularly endothelin-converting enzyme inhibition, should be explored as means by which to reduce vascular tone and blood pressure in patients with CRF.

Novel mutations in the 3 region of the polycystic kidney disease 1 (PKD1) gene.

Mutation screening in 90 unrelated ADPKD1 patients was carried out on some of the exons in the single copy area (37, 38, 39, 44, 45) using genomic PCR and SSCP. Four novel mutations were found: a 15 bp in-frame deletion in exon 39 [nt11449 (del 15)], a 2 bp deletion in exon 44 [nt12252 (del 2)], a G insertion in exon 44 [nt12290 (Ins G)], and a GTT in-frame deletion in exon 45 [nt12601 (del 3)].

Impairment of forearm vasodilatation to acetylcholine in hypercholesterolemia is reversed by aspirin.

OBJECTIVE: Impaired cholinergic vasodilatation in the forearm in hypertension and hypercholesterolemia has been attributed to impaired nitric oxide bioavailability. However, inhibition of cyclooxygenase reverses the impaired cholinergic dilatation in hypertensive animals and patients. The aim of this study was to examine the effect of aspirin on cholinergic vasodilatation in hypercholesterolemic patients. METHODS: We examined responses to brachial artery infusion of acetylcholine and the endothelium-independent vasodilator sodium nitroprusside in the presence or absence of aspirin in 10 hypercholesterolemic patients (7 men/3 women; aged 38-63 yr; systolic blood pressure 133 +/- 5 mmHg; diastolic blood pressure 80 +/- 3) compared with 10 matched controls (7 men/3 women; aged 38-63 yr; systolic blood pressure 126 +/- 2; diastolic blood pressure 77 +/- 2). RESULTS: In hypercholesterolemic patients, forearm vasodilatation was impaired in response to acetylcholine (112 +/- 20 vs. 346 +/- 30% increase in blood flow in controls, at the highest dose [15 micrograms min-1]; P < 0.0001) but not in response to sodium nitroprusside. With the addition of aspirin, baseline forearm blood flow was unaltered. However, forearm vasodilatation to acetylcholine was partially restored in hypercholesterolemics (from 112 +/- 20 to 193 +/- 30%; P < 0.001) though not affected in controls. Vasodilator responses to sodium nitroprusside were unaffected by aspirin in either group. CONCLUSIONS: In hypercholesterolemia, an altered balance between vasoconstrictor and dilator prostanoids, favouring constrictors, may contribute to endothelial dysfunction either directly or through an effect on nitric oxide synthesis. Restoration of this imbalance may be a component of the therapeutic benefit of aspirin in cardiovascular disease.

Duration of effects of dietary fish oil supplementation on serum eicosapentaenoic acid and docosahexaenoic acid concentrations in dogs.

OBJECTIVE: To determine how long serum concentrations of omega-3 fatty acids remain elevated after cessation of dietary fish oil supplementation. ANIMALS: 12 healthy Beagles. PROCEDURE: Baseline serum concentrations of linoleic acid, linolenic acid, arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) were measured. Dogs were then fed a diet supplemented with soybean oil or fish oil for 8 weeks, and serum fatty acid concentrations were measured while dogs were fed the experimental diets and for 18 weeks after they were switched to a maintenance diet. RESULTS: For dogs fed the fish oil diet, serum EPA and DHA concentrations were significantly increased by week 1 and remained increased for 7 (DHA concentration) or 3 (EPA concentration) weeks after dietary fish oil supplementation was discontinued. CONCLUSIONS: In dogs, supplementation of the diet with fish oil may have effects for several weeks after dietary supplementation is discontinued. CLINICAL RELEVANCE: Studies of the effects of fish oil supplementation that use a crossover design should allow for an appropriate washout period.