Lethal control of an apex predator has unintended cascading effects on forest mammal assemblages.

Disruption to species-interaction networks caused by irruptions of herbivores and mesopredators following extirpation of apex predators is a global driver of ecosystem reorganization and biodiversity loss. Most studies of apex predators' ecological roles focus on effects arising from their interactions with herbivores or mesopredators in isolation, but rarely consider how the effects of herbivores and mesopredators interact. Here, we provide evidence that multiple cascade pathways induced by lethal control of an apex predator, the dingo, drive unintended shifts in forest ecosystem structure. We compared mammal assemblages and understorey structure at seven sites in southern Australia. Each site comprised an area where dingoes were poisoned and an area without control. The effects of dingo control on mammals scaled with body size. Activity of herbivorous macropods, arboreal mammals and a mesopredator, the red fox, were greater, but understorey vegetation sparser and abundances of small mammals lower, where dingoes were controlled. Structural equation modelling suggested that both predation by foxes and depletion of understorey vegetation by macropods were related to small mammal decline at poisoned sites. Our study suggests that apex predators' suppressive effects on herbivores and mesopredators occur simultaneously and should be considered in tandem in order to appreciate the extent of apex predators' indirect effects.

Déficit de vitamina D en pacientes post-menopáusicas y su relación con el metabolismo fosfocálcico y la osteoporosis / Vitamin D deficiency in post-menopausal patients and its relation with the mineral metabolism and the osteoporosis

La influencia de la hipovitaminosis D en la mujer post-menopáusica constituye un tema de gran importancia por las implicancias en el metabolismo fosfo-cálcico y su posible asociación en el desarrollo de otros tipos de patologías. Es por eso que el presente estudio tiene por objetivo conocer la prevalencia de la hipovitaminosis D en una población de mujeres post-menopáusicas y su asociación con los cambios en el metabolismo fosfocálcico y con el desarrollo de la osteoporosis. Se incluyó 67 mujeres post-menopáusicas procedentes de una consulta ambulatoria de reumatología. Se consideraron las siguientes variables clínicas (i.e. edad, peso), laboratorio (i.e. concentraciones de calcio, fosforo y PTH) y la presencia o ausencia de osteopenia u osteoporosis. El valor de la media de la edad de las pacientes fue de 66 ± 11,29 años y las concentraciones de vitamina D inferior a 30 ng/ml se observó en 50 (74,6%) pacientes. La osteopenia u osteoporosis se observó en una parte importante de nuestros pacientes. No se observó una correlación significativa entre las concentraciones de vitamina D y las concentraciones de calcio y fósforo. Se observó una correlación negativa en relación a las concentraciones de PTH (P= 0,049). Las pacientes con osteoporosis u osteopenia presentan con frecuencia hipovitaminosis D. Es por eso que existe la necesidad de realizar una detección y tratamiento temprano a fin de evitar las graves complicaciones que podrían acompañar a la pérdida de densidad ósea en este grupo de pacientes.

Diagnostic value of history taking in reflex syncope.

The medical history, in combination with the physical examination and a 12-lead electrocardiogram, plays a key role in the diagnosis and risk stratification of patients with syncope. However, diagnostic clinical criteria are not uniformly applied. In older studies, the diagnostic criteria for vasovagal or reflex syncope often included typical precipitating events and warning symptoms. More recent studies have documented that a variety of unrecognized stressors can trigger reflex syncope and that warning signs and symptoms may be minimal. A characteristic medical history (a trigger and/or prodromi) is enough to diagnose reflex syncope if the risk for a cardiac cause of syncope is low (e. g. patients < 65 yrs, without a history of heart disease and no ECG abnormalities). In elderly subjects with a higher risk of cardiac syncope, the yield of the medical history is lower. However, a prospective study of the value of the medical history for the diagnosis of syncope with long-term follow-up has not been performed.

Epidemiology of reflex syncope.

Cost-effective diagnostic approaches to reflex syncope require knowledge of its frequency and causes in different age groups. For this purpose we reviewed the available literature dealing with the epidemiology of reflex syncope. The incidence pattern of reflex syncope in the general population and general practice is bimodal with peaks in teenagers and in the elderly. In the young almost all cases of transient loss of consciousness are due to reflex syncope. The life-time cumulative incidence in young females ( congruent with 50 %) is about twice as high as in males ( congruent with 25 %). In the elderly, cardiac causes, orthostatic and postprandial hypotension, and the effects of medications are common, whereas typical vasovagal syncope is less frequent. In emergency departments, cardiac causes and orthostatic hypotension are more frequent especially in elderly subjects. Reflex syncope, however, remains the most common cause of syncope, but all-cause mortality in subjects with reflex syncope is not higher than in the general population. This knowledge about the epidemiology of reflex syncope can serve as a benchmark to develop cost-effective diagnostic approaches.

A patient with recurrent syncope and ST-elevation on the electrocardiogram.

A 56-year old woman had over 100 episodes of syncope since the age of 8. Because the patient's description of the episodes suggested vasovagal syncope she was studied by a head up tilt test (HUT). Seconds after the uncomplicated HUT the patient experienced a typical syncope with bradycardia, marked ST-elevation and chest pain. After treatment with nifedipine she has had one syncopal spell in a follow up period of 31 months. We conclude that the syncopal events in this patient were caused by a combination of vasovagal syncope and coronary spasm.

Addition of salmeterol to fluticasone propionate treatment in moderate-to-severe asthma.

This study was designed to determine whether the benefit of adding salmeterol was superior to doubling the dose of fluticasone propionate (FP) over 6 months, compared to a control group who remained on a lower dose of FP. The multi-centre, double-blind, parallel group study involved 496 symptomatic asthmatic patients with a history of exacerbations on 500-800 micrograms (microg) inhaled corticosteroids (ICS) twice daily (b.d.) in a broadly representative group of 100 hospitals and general practices in six countries. Two doses of FP--250 microg b.d. (FP250) or 500 microg b.d. (FP500)--were compared with the lower dose of FP plus a long-acting beta2-agonist, salmeterol 50 microg b.d. (SM/FP250). Patients symptomatic on the run-in dose of FP250 alone formed the control group in the treatment period. Over 6 months, SM/FP250 significantly improved mean morning peak expiratory flow rates (amPEF) by 42.1 l/min, more than twice the improvement achieved with either dose of FP alone. SM/FP250 also resulted in more symptom-free days and nights (P < 0.002) and days and nights with no relief medication (P < 0.001). The number of severe exacerbations was low: 3, 6 and 8% in the SM/FP250, low- and high-dose FP groups, respectively. This study confirms that adding salmeterol to low-dose inhaled FP offers greater improvements than either maintaining or doubling the dose of FP. Significant benefit was gained from adding salmeterol in a group of patients who appeared to have been at the top of their steroid dose-response curve receiving FP250. There was no evidence of tolerance and a low incidence of exacerbations in all treatment groups.

Pilots with vasovagal syncope: fit to fly?

Two pilots who had experienced vasovagal syncope were grounded by the aeromedical service. Pilot A had experienced three episodes of syncope in medical settings, none during flight. Pilot B had experienced four episodes of syncope in emotional/medical settings, one during flight. Whether a pilot who experienced one or more episodes of vasovagal syncope is declared fit to fly now depends on the number of episodes experienced. We propose that pilots should be assessed individually. Certainty of the diagnosis of vasovagal syncope, the chance and predictability of recurrences during flight, and the possibility of effective therapy should be assessed. Chance of recurrence during flight is low when the triggering factor is known and avoidable. Pilots with syncopal episodes in predictable (e.g., medical) situations, with clear prodromal symptoms and/or effective therapy, should be declared fit to fly. A symptom-free period and/or restriction to fly 'as or with a co-pilot' can be considered.

[A patient with an unexplained loss of consciousness: a case for the neurologist or the cardiologist?]. / Een patiënt met een onbegrepen wegraking: voor de neuroloog of de cardioloog?

Three patients, a woman aged 62 and two men aged 22 and 77 years respectively, were admitted because of an unexplained loss of consciousness. In the woman and younger man these complaints were caused by a vasovagal reaction, and in the older man by hypersensitivity of the carotid sinus. In a hospital setting, the examination of patients with a loss of consciousness often leads to discussions between the neurologist and the cardiologist. Elaborate additional testing seldom reveals epilepsy or cardiac arrhythmia as the cause. A thorough medical history can exclude both diagnoses in almost all cases. Physicians should be aware that most patients experience a vasovagal syncope and that this might be triggered by very common circumstances. Knowledge of these triggers and the epidemiology of loss of consciousness might prevent the patients from being examined by different specialists and undergoing unnecessary additional tests.

Multiple myeloma disrupts the TRANCE/ osteoprotegerin cytokine axis to trigger bone destruction and promote tumor progression.

Bone destruction, caused by aberrant production and activation of osteoclasts, is a prominent feature of multiple myeloma. We demonstrate that myeloma stimulates osteoclastogenesis by triggering a coordinated increase in the tumor necrosis factor-related activation-induced cytokine (TRANCE) and decrease in its decoy receptor, osteoprotegerin (OPG). Immunohistochemistry and in situ hybridization studies of bone marrow specimens indicate that in vivo, deregulation of the TRANCE-OPG cytokine axis occurs in myeloma, but not in the limited plasma cell disorder monoclonal gammopathy of unknown significance or in nonmyeloma hematologic malignancies. In coculture, myeloma cell lines stimulate expression of TRANCE and inhibit expression of OPG by stromal cells. Osteoclastogenesis, the functional consequence of increased TRANCE expression, is counteracted by addition of a recombinant TRANCE inhibitor, RANK-Fc, to marrow/myeloma cocultures. Myeloma-stroma interaction also has been postulated to support progression of the malignant clone. In the SCID-hu murine model of human myeloma, administration of RANK-Fc both prevents myeloma-induced bone destruction and interferes with myeloma progression. Our data identify TRANCE and OPG as key cytokines whose deregulation promotes bone destruction and supports myeloma growth.

Low serum and red blood cell folate are moderately, but nonsignificantly associated with increased risk of invasive cervical cancer in U.S. women.

Previous observational epidemiologic studies of folate and cervical cancer, as well as folate supplementation trials for cervical dysplasia, have produced mixed results. We examined the relationship between serum and RBC folate and incident invasive cervical cancer in a large, multicenter, community-based case-control study. Detailed in-person interviews were conducted, and blood was drawn at least 6 mo after completion of cancer treatment from 51% of cases and 68% of controls who were interviewed. Blood folate was measured with both microbiologic and radiobinding assays. Included in the final analyses were 183 cases and 540 controls. Logistic regression was used to control for all accepted risk factors, including age, sexual behavior, smoking, oral contraceptive use, Papanicolaou smear history and human papillomavirus (HPV)-16 serology. For all four folate measures, the geometric mean in cases was lower than in controls (e.g., 11.6 vs. 13.0 nmol/L, P < 0.01 for the serum radiobinding assay). Folate measures using microbiologic and radiobinding assays were correlated (serum: r = 0.90; RBC: r = 0.77). For serum folate, multivariate-adjusted odds ratios (OR) in the lowest vs. highest quartile were 1.3 [95% confidence interval (CI) = 0.8--2.9] and 1.6 (0.9--2.9), using the microbiologic and radiobinding assays, respectively. For RBC folate, comparable OR were 1.2 (0.6--2.2) and 1.5 (0.8--2.7). Similar risks were obtained when restricting analyses to subjects with a history of HPV infection. Thus, low serum and RBC folate were each moderately, but nonsignificantly, associated with increased invasive cervical cancer risk. These findings support a role for one-carbon metabolism in the etiology of cervical cancer.

L206W mutation of the cystic fibrosis gene, relatively frequent in French Canadians, is associated with atypical presentations of cystic fibrosis.

Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Over 400 mutations have been reported at this locus. Although severe forms of cystic fibrosis are usually associated with pancreatic insufficiency, pulmonary dysfunction, and elevated sweat chloride, there is a wide range of phenotypes, including congenital absence of the vas deferens, observed with some of the milder mutations. The L206W mutation, which was first identified in patients from South France, is relatively frequent in French Canadians from Quebec. In this report, we document the atypical form of cystic fibrosis associated with this mutation, in a cohort of 7 French Canadian probands.

Performance of Gem Premier blood gas/electrolyte analyzer evaluated.

We evaluated a new analyzer designed for point-of-care testing of blood gases, sodium, potassium, ionized calcium, and hematocrit. The Gem Premier (Mallinckrodt) system has two components: the analyzer and a disposable cartridge. Analysis takes place in the cartridge, which contains the electrochemical sensors, the calibrants, the reagents, the sampling stylus, and the waste container. The system was evaluated for imprecision and accuracy. With aqueous control materials, total imprecision (CV) was: pH, 0.10-0.18%; PCO2, 3.16-5.78%; PO2, 2.92-4.85%; sodium, 0.82-1.44%; potassium, 1.35-1.48%; ionized calcium, 0.75-1.45%; and hematocrit, 1.13-1.83%. Accuracy of the system was assessed by split-sample comparison with the Radiometer ABL 330 blood gas analyzer for pH and blood gases, the Nova Stat Profile 5 for whole-blood electrolyte and hematocrit analysis, and the IL Phoenix for plasma electrolyte analysis. After outlier correction, regression statistics were excellent for all analytes except sodium, which demonstrated Sy[x values between 1.80 and 2.30 mmol/L and 0.85 < or = r < 0.90.

Computed tomography in the early detection of asbestosis.

Computed tomography (CT; both conventional (CCT) and high resolution (HRCT)) scans of the thorax were evaluated to detect early asbestosis in 61 subjects exposed to asbestos dust in Québec for an average of 22(3) years and in five controls. The study was limited to consecutive cases with chest radiographs of the International Labour Organisation categories 0 or 1 determined independently. All subjects had a standard high kilovoltage posteroanterior and lateral chest radiograph, a set of 10-15 1 cm collimation CCT scans and a set of three to five 2 mm collimation HRCT scans in the upper, middle, and lower lung fields. Five experienced readers independently read each chest radiograph and sets of CT scans. On the basis of three to five readers agreeing for small opacities of the lung parenchyma, 12/46 (26%) negative chest radiographs were positive on CT scans, but 6/18 (33%) positive chest radiographs were negative on CT scan. On the basis of four to five readers agreeing on a chest radiograph, 36/66 (54%) subjects were normal (group A), 17/66 (26%) were indeterminate (group B), and 13/66 (20%) were abnormal (group C). By the combined readings of CCT and HRCT, 4/31 (13%) asbestos exposed subjects of group A were abnormal (p < 0.001), 6/17 (35%) of group B were abnormal, and in group C, 1/13 (8%) was normal, 2/13 were indeterminate, and 10/13 (77%) were abnormal. Separate readings of CCT and HRCT on distinct films in 14 subjects showed that all cases of asbestosis were abnormal on both CCT and HRCT. Inter-reader analyses by kappa statistics showed significantly better agreement for the readings of CT than the chest radiographs (p < 0.001), and for the reading of CCT than HRCT (p < 0.01). Thus CT scans of the thorax identifies significantly more irregular opacities consistent with the diagnosis of asbestosis than the chest radiograph (20 cases on CT scans v 13 on chest radiographs when four to five readers agreed, 13% of asbestos exposed subjects with normal chest radiographs or 21% of asbestos exposed subjects with normal or near normal chest radiographs. It decreased the number of indeterminate cases significantly from 17 on chest radiographs to 13 on CT scans. All cases of asbestosis detected only on CT scans were similarly seen on CCT and HRCT and did not have significant changes in lung function. The CT scans significantly reduced the inter-reader variability, despite the absence of ILO type reference films for these scans.

Passive immunotherapy in the treatment of advanced human immunodeficiency virus infection.

To evaluate the safety and efficacy of passive immunotherapy for advanced human immunodeficiency virus (HIV) infection, a randomized, double-blind, controlled trial of human anti-HIV hyperimmune plasma was conducted. Sixty-three subjects with stage IV HIV disease (AIDS) were randomized to received 250 mL of either HIV-immune plasma or HIV antibody-negative plasma every 4 weeks. Although nonsignificant trends toward improved survival and delayed occurrence of a new opportunistic infection were noted, no significant effects on absolute CD4 lymphocyte counts or quantitative HIV viremia were seen. The only notable toxicity was the allergenicity to be expected from infusing plasma products, usually manifesting as urticaria. Thus, results do not rule out the potential usefulness of passive immunization with different preparations, but did fail to demonstrate clinical benefit of the product studied.

Analytical evaluation of i-STAT Portable Clinical Analyzer and use by nonlaboratory health-care professionals.

We evaluated the performance of the i-STAT Portable Clinical Analyzer, a hand-held instrument that, with its current cartridge, analyzes for electrolytes, urea nitrogen, glucose, and hematocrit in approximately 60 microL of whole blood in approximately 90 s. Accuracy, imprecision, and linearity studies were performed with aqueous controls and standards and by split-sample analysis. Intrarun imprecision (CV) ranged from 0.34% to 3.97%. Total imprecision over a 2-month period ranged from 0.42% to 4.83%, with urea nitrogen and glucose analyses generating the higher values. Patients' results from the Portable Clinical Analyzer correlated well with those obtained for whole blood or plasma by the Nova Stat Profile 5, the Beckman Synchron CX3, or the Technicon H1 Hematology Analyzer, with Sylx values < 0.2 mmol/L for potassium; < 1.5 mmol/L for sodium, glucose, and urea nitrogen; < 2.4 mmol/L for chloride, and < 2.4% for hematocrit. We also ascertained imprecision and accuracy of the system placed in a cardiothoracic intensive-care unit and operated by nurses. There were no significant differences in either the imprecision or accuracy of the system in this setting. We conclude that operator technique is not a factor in the analytical performance of the system and that it can be used by nonlaboratorians with a high degree of confidence that reliable results will be obtained.

Single lung transplantation for cystic fibrosis: is it an option? Cystic Fibrosis Transplant Study Group.

A 15-year-old girl with end-stage lung disease from cystic fibrosis underwent a bilateral lung transplantation. Infarction of the left lung allograft required its removal on day 10. The patient went on to have an uneventful recovery except for a prolonged air leak from the right allograft of approximately 29 days. The left pleural cavity opacified with time with no clinical or radiologic evidence of empyema. The patient was discharged on day 35 in good condition. On a follow-up examination 6 months after transplantation, she appeared to be functioning extremely well with a single lung allograft. This case report challenges the conventional wisdom that bilateral pneumonectomy and single lung transplantation are not an option to be considered for patients with cystic fibrosis or bronchiectasis.

Maternal vitamin levels during pregnancies producing infants with neural tube defects.

Women at very high risk for having a child with a neural tube defect (NTD) because they had previously delivered affected children significantly reduced their recurrence rate by taking folate supplements before conception. To clarify how these results might apply to a lower-risk general obstetric population, we measured folate, vitamin B12, and retinol levels in maternal serum drawn early in 89 pregnancies resulting in NTD offspring and 178 control pregnancies identified from the Finnish Registry of Congenital Malformations. In 86.5% of the subjects, specimens were collected within 8 weeks after neural tube closure. In the NTD case mothers the mean (+/- SD) levels were not significantly lower than in control mothers: folate, 4.13 +/- 2.36 versus 4.28 +/- 2.52 ng/ml; vitamin B12, 482.8 +/- 161.1 versus 520.3 +/- 191.9 pg/ml; and retinol, 51.2 +/- 17.0 versus 50.5 +/- 16.9 micrograms/dl. After adjustment for age of the specimen, gestational age at which the specimen was drawn, maternal age, and maternal employment status, the odds ratios for being a case mother were 1.00 (95% confidence interval (CI) 0.91 to 1.10) for folate, 1.05 (95% CI 0.92 to 1.19) for vitamin B12, and 0.99 (95% CI 0.88 to 1.10) for retinol. Excluding NTD cases with known or suspected causes unrelated to vitamins, restricting the analyses to interviewed subjects, and excluding subjects whose specimens were collected after 15 gestational weeks confirmed that NTD case and control vitamin levels did not differ significantly. This population-based investigation in a low rate area demonstrated no relationship between maternal serum folate, vitamin B12, or retinol levels during pregnancy and the risk of NTDs.

Folate, vitamin C, and cervical intraepithelial neoplasia.

A case-control study was designed to assess the relationship between cervical intraepithelial neoplasia (CIN) and folate in serum, red blood cells, and diet. The association between CIN and dietary vitamin C was also investigated. Cases were selected from women with biopsy-confirmed CIN. Controls were age-, race-, and clinic-matched women with normal cervical (Pap) smears. Study participants completed self-administered food frequency (n = 100 matched pairs) and health (n = 102 matched pairs) questionnaires. Fasting venous blood samples were collected for serum (n = 98 matched pairs) and red cell (n = 68 matched pairs) folate assays. Conditional logistic regression models were used to estimate crude odds ratios and odds ratios adjusted for smoking, income, number of sexual partners, frequency of cervical smear, use of spermicidal contraceptive agents, history of genital warts, and Quetelet index. Dietary intake variables were adjusted for total energy intake prior to logistic regression. A protective effect of red cell folate was evident with adjusted odds ratios (95% confidence intervals) of 0.1 (0.0-0.4), 0.6 (0.2-2.0), and 0.5 (0.2-1.9) for those in quartiles 4 (highest), 3, and 2 compared to quartile 1 (lowest). Supporting evidence for the protective effect of folate was provided by inverse associations between CIN and folate in both serum and diet. An inverse association was also found between CIN and dietary vitamin C with adjusted odds ratios (95% confidence intervals) of 0.2 (0.0-0.7), 0.6 (0.2-1.6), and 0.6 (0.2-1.8) for those in quartiles 4, 3, and 2, respectively, compared to quartile 1. These findings support dietary recommendations, such as those of the American Cancer Society, the National Cancer Institute, and the U.S. Dietary Guidelines, which allow for adequate intake of folate and vitamin C, both of which are found in good quantity in fruits and vegetables. Increased consumption of legumes and whole grains is also in accord with current dietary recommendations, and both of these types of foods are good sources of folates.