Environmental conditions regulate the impact of plants on cloud formation.

The terrestrial vegetation emits large amounts of volatile organic compounds (VOC) into the atmosphere, which on oxidation produce secondary organic aerosol (SOA). By acting as cloud condensation nuclei (CCN), SOA influences cloud formation and climate. In a warming climate, changes in environmental factors can cause stresses to plants, inducing changes of the emitted VOC. These can modify particle size and composition. Here we report how induced emissions eventually affect CCN activity of SOA, a key parameter in cloud formation. For boreal forest tree species, insect infestation by aphids causes additional VOC emissions which modifies SOA composition thus hygroscopicity and CCN activity. Moderate heat increases the total amount of constitutive VOC, which has a minor effect on hygroscopicity, but affects CCN activity by increasing the particles' size. The coupling of plant stresses, VOC composition and CCN activity points to an important impact of induced plant emissions on cloud formation and climate.

Atmospheric benzenoid emissions from plants rival those from fossil fuels.

Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functions of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y(-1)), pointing to the importance of these natural emissions in atmospheric physics and chemistry.

Detection of diseased plants by analysis of volatile organic compound emission.

This review focuses on the detection of diseased plants by analysis of volatile organic compound (VOC) emissions. It includes an overview of studies that report on the impact of infectious and noninfectious diseases on these emissions and discusses the specificity of disease-induced emissions. The review also provides an overview of processes that affect the gas balance of plant volatiles, including their loss processes. These processes are considered as important because they contribute to the time-dynamic concentration profiles of plant-emitted volatiles. In addition, we describe the most popular techniques currently in use to measure volatiles emitted from plants, with emphasis on agricultural application. Dynamic sampling coupled with gas chromatography and followed by an appropriate detector is considered as the most appropriate method for application in agriculture. It is recommended to evaluate the state-of-the-art in the fields concerned with this method and to explore the development of a new instrument based on the specific needs for application in agricultural practice. However, to apply such an instrument in agriculture remains a challenge, mainly due to high costs.

Release of lipoxygenase products and monoterpenes by tomato plants as an indicator of Botrytis cinerea-induced stress.

Changes in emission of volatile organic compounds (VOCs) from tomato induced by the fungus Botrytis cinerea were studied in plants inoculated by spraying with suspensions containing B. cinerea spores. VOC emissions were analysed using on-line gas chromatography-mass spectrometry, with a time resolution of about 1 h, for up to 2 days after spraying. Four phases were delimited according to the starting point and the applied day/night rhythm of the experiments. These phases were used to demonstrate changes in VOC flux caused by B. cinerea infestation. Tomato plants inoculated with B. cinerea emitted a different number and amount of VOCs after inoculation compared to control plants that had been sprayed with a suspension without B. cinerea spores. The changes in emissions were dependent on time after inoculation as well as on the severity of infection. The predominant VOCs emitted after inoculation were volatile products from the lipoxygenase pathway (LOX products). The increased emission of LOX products proved to be a strong indicator of a stress response, indicating that VOC emissions can be used to detect plant stress at an early stage. Besides emission of LOX products, there were also increases in monoterpene emissions. However, neither increased emission of LOX products nor of monoterpenes is specific for B. cinerea attack. The emission of LOX products is also induced by other stresses, and increased emission of monoterpenes seems to be the result of mechanical damage induced by secondary stress impacts on leaves.

Rapid oral desensitisation procedure in clopidogrel hypersensitivity.

We describe a patient who developed generalised pruritus with oedema and rash two weeks after she had started taking clopidogrel following coronary stent implantation. In the absence of other likely causative agents, clopidogrel hypersensitivity was probable. She was treated with a rapid oral desensitisation procedure, after which a daily dose of 75 mg clopidogrel was well tolerated. No major adverse events occurred during a follow-up period of eight months. Oral desensitisation in clopidogrel hypersensitivity seems to be a safe method to reduce the risk of coronary stent thrombosis. (Neth Heart J 2008;16:21-3.).

Methanol emissions from deciduous tree species: dependence on temperature and light intensity.

Methanol emissions from several deciduous tree species with predominantly mature leaves were measured under laboratory and field conditions. The emissions were modulated by temperature and light. Under constant light conditions in the laboratory, methanol emissions increased with leaf temperature, by up to 12% per degree. At constant temperatures, emissions doubled when light intensity (PAR) increased from darkness to 800 micromol x m(-2) x s(-1). A phenomenological description of light and temperature dependencies was derived from the laboratory measurements. This description was successfully applied to reproduce the diel cycle of methanol emissions from an English oak measured in the field. Labelling experiments with (13)CO(2) provided evidence that less than 10% of the emitted methanol was produced de novo by photosynthesis directly prior to emission. Hence, the light dependence of the emissions cannot be explained by instantaneous production from CO(2) fixation. Additional experiments with selective cooling of plant roots indicated that a substantial fraction of the emitted methanol may be produced in the roots or stem and transported to stomata by the transpiration stream. However, the transpiration stream cannot be considered as the main factor that determines methanol emissions by the investigated plants.

Stomatal uptake and stomatal deposition of ozone in isoprene and monoterpene emitting plants.

Volatile isoprenoids were reported to protect plants against ozone. To understand whether this could be the result of a direct scavenging of ozone by these molecules, the stomatal and non-stomatal uptake of ozone was estimated in plants emitting isoprene or monoterpenes. Ozone uptake by holm oak (Quercus ilex, a monoterpene emitter) and black poplar (Populus nigra, an isoprene emitter) was studied in whole plant enclosures (continuously stirred tank reactors, CSTR). The ozone uptake by plants was estimated measuring ozone concentration at the inlet and outlet of the reactors, after correcting for the uptake of the enclosure materials. Destruction of ozone at the cuticle or at the plant stems was found to be negligible compared to the ozone uptake through the stomata. For both plant species, a relationship between stomatal conductance and ozone uptake was found. For the poplar, the measured ozone losses were explained by the uptake of ozone through the stomata only, and ozone destruction by gas phase reactions with isoprene was negligible. For the oak, gas phase reactions of ozone with the monoterpenes emitted by the plants contributed significantly to ozone destruction. This was confirmed by two different experiments showing a) that in cases of high stomatal conductance but under low CO(2) concentration, a reduction of monoterpene emission was still associated with reduced O(3) uptake; and b) that ozone losses due to the gas phase reactions only can be measured when using the exhaust from a plant chamber to determine the gas phase reactivity in an empty reaction chamber. Monoterpenes can therefore relevantly scavenge ozone at leaf level contributing to protection against ozone.

Simultaneous growth and emission measurements demonstrate an interactive control of methanol release by leaf expansion and stomata.

Emission from plants is a major source of atmospheric methanol. Growing tissues contribute most to plant-generated methanol in the atmosphere, but there is still controversy over biological and physico-chemical controls of methanol emission. Methanol as a water-soluble compound is thought to be strongly controlled by gas-phase diffusion (stomatal conductance), but growth rate can follow a different diurnal rhythm from that of stomatal conductance, and the extent to which the emission control is shared between diffusion and growth is unclear. Growth and methanol emissions from Gossypium hirsutum, Populus deltoides, and Fagus sylvatica were measured simultaneously. Methanol emission from growing leaves was several-fold higher than that from adult leaves. A pronounced diurnal rhythm of methanol emission was observed; however, this diurnal rhythm was not predominantly determined by the diurnal rhythm of leaf growth. Large methanol emission peaks in the morning when the stomata opened were observed in all species and were explained by release of methanol that had accumulated in the intercellular air space and leaf liquid pool at night in leaves with closed stomata. Cumulative daily methanol emissions were strongly correlated with the total daily leaf growth, but the diurnal rhythm of methanol emission was modified by growth rate and stomatal conductance in a complex manner. While in G. hirsutum and in F. sylvatica maxima in methanol emission and growth coincided, maximum growth rates of P. deltoides were observed at night, while maximum methanol emissions occurred in the morning. This interspecific variation was explained by differences in the share of emission control by growth processes, by stomatal conductance, and methanol solubilization in tissue water.

Histopathologic, stereologic, epidemiologic, and clinical parameters in the prognostic evaluation of squamous cell carcinoma of the oral cavity.

BACKGROUND: Prognostic indicators that could assist in a more precise selection of patients with oral cancer for differentiated therapy would be clinically valuable. METHODS: A consecutive series of 161 cases of intraoral squamous cell carcinoma (SCC) occurring during a 5-year period in a population of 1.4 million inhabitants, was evaluated by histopathologic (the modified classification of Jakobsson et al.), stereologic, clinical, and epidemiologic parameters and the serum markers hemoglobin and rhesus blood group. RESULTS: Univariate analysis established a significant prognostic value in terms of cause-specific survival for T stage (P < .0001), stage (P < .0001), maximum tumor diameter (P < .0001), N stage (N+/NO) (P < .0001), alcohol consumption (P = .03), stereologic estimates of nuclear volume (P = .04), and the histomorphologic parameters mode of invasion (P = .001), pattern (P = .01), vascular invasion (P = .02), depth (P = .006), and mean histologic score. Tobacco consumption was borderline significant (P = .055). A multivariate analysis using the Cox proportional hazard analysis showed that both clinical (stage, P < .0001; size, P = .0027), epidemiologic (tobacco consumption, P = .0054), morphohistopathologic (mode of invasion P < .0001), and stereologic (nuclear volume, P = .0010) parameters had an independent significant effect on survival. Inversely, the mean histologic score had no prognostic value. From the final regression model prognostic forecasts were calculated. Twelve patients (25%) with stage I disease had unfavorable histologic and stereologic parameters. The observed survival (+/- 1 standard error of the estimate) for these patients was 33% +/- 18%. The observed survival for stage I patients with more favorable histologic and stereologic characteristics (n = 36) was 76% +/- 8%. CONCLUSION: The use of a combination of clinical, histologic, epidemiologic, and stereologic parameters will assist the design of treatment strategies for intraoral SCC.

[Consumption of tobacco and alcohol as prognostic factors in oral cancer]. / Tobaks- og alkoholforbrug som prognostiske faktorer ved oral cancer.

The aim of the study was to assess the potential prognostic value of tobacco and alcohol consumption. 161 consecutive patients with intra-oral squamous cell carcinoma were included in a prospective follow-up study and valid data on tobacco and alcohol consumption were obtained. Univariate analysis showed that alcohol consumption had a significant influence and tobacco consumption had a borderline significant influence on the prognosis. Tobacco and alcohol consumption were strong correlated and each of these correlated to sex. Clinical staging (TNM), tumor size and sex all had a significant prognostic impact. A multivariate analysis showed that clinical stage, tumor size and tobacco consumption, but not alcohol consumption had significant influence on the prognosis. Thus tobacco smoking is an important clinical parameter both from a prophylactic and a therapeutic point of view.

Delay in the diagnosis of oral squamous cell carcinoma.

Delay in diagnosis was recorded prospectively in 167 patients with an oral squamous cell carcinoma. The median total delay was 4 months of which two-thirds was patient delay. The corrected survival did not correlate with the total delay. The patient delay was not significantly correlated with tumour or patient factors and the unreliable nature of patient delay information makes such data clinically unusable. In contrast, the professional delay correlated significantly with some of these factors. The delay was longer for women than for men and the older the patient, the longer the delay. The professional delay was longest in patients with small tumours. Thus, registration of the professional delay provides information to be used to improve the diagnostic efficiency of the health care system.

Lignan and isoflavonoid conjugates in human urine.

Lignans and isoflavonoids are two groups of diphenolic phytoestrogens of plant origin which have gained increasing interest because of their possible cancer protective properties. High excretion of these compounds occur in populations at low risk of breast, prostate and colon cancer consuming either high amounts of whole-grain (lignans and some isoflavonoids) or soy products (isoflavonoids and some lignans). We determined the pattern of conjugation of the phytoestrogens in four urine samples from vegetarian or semivegetarian women and in two samples from men. Seven compounds were investigated: enterodiol, enterolactone, matairesinol, diadzein, equol, genistein and O-desmethylangolensin. The fractions quantified are the free fraction, mono- and disulfate, as well as the mono-, di- and sulfoglucuronide fractions. For the fractionation and purification we used ion-exchange chromatography and the determination of the concentrations of each compound in all fractions was done by isotope dilution gas chromatography-mass spectrometry (GLC-MS) using deuterated internal standards of all diphenols. More than 60% of all compounds determined, occurred in the monoglucuronide fraction. Daidzein, enterodiol and equol are excreted to a relatively high extent as sulfoglucuronides and genistein as diglucuronide. We conclude that the general pattern of lignan and isoflavonoid conjugates in urine is similar to that of endogenous estrogens.

Case-control study of squamous cell cancer of the oral cavity in Denmark.

A population-based case-control study was designed to examine if the risk of developing intra-oral squamous-cell carcinoma in Denmark was associated with occupation, marital status, residence, dental status, and exposure to coffee, tea, tobacco, and alcohol. Cases consisted of 161 consecutively-admitted incident patients with histologically verified, primary, intra-oral squamous-cell carcinoma treated at the Aarhus University Hospital from January 1986 to November 1990. For each case, three controls of the same gender and age were selected randomly from among nonhospitalized residents in the hospital's catchment area (some 1.4 m inhabitants). Four hundred of the selected 483 controls participated in the study. Risk was associated significantly with marital status, residence, dental status, alcohol consumption, and exposure to tobacco. When correcting for tobacco and alcohol consumption, only marital status and dental status remained significant. The association between risk and marital status was particularly prominent among divorced compared with married persons (odds ratio [OR] = 2.3, 95 percent confidence interval [CI] = 1.1-4.6). Persons with less than five teeth had an OR of 2.4 (CI 1.3-4.1) compared with persons with 15 or more teeth. Tobacco and alcohol exposure were the strongest individual risk-indicators in both lifetime and current consumption estimates, and their composite effect was particularly strong. Compared with nonusers, OR for tobacco (> 20 g/d) adjusted for alcohol = 5.8 (CI = 3.1-10.9); OR for alcohol (> 5 drinks/d) adjusted for tobacco = 8.4 (CI = 4.0-17.6). The OR for heavy users of tobacco and alcohol (> 20 g tobacco/d and > 5 drinks/d) was 80.7 (CI = 21.8-298.8). These results confirm that tobacco and alcohol contribute significantly to the risk of developing oral cancer. There were no significant differences between the risk estimates for the two genders or young and old persons. Two simulation studies indicate that the observed risk associated with tobacco and alcohol consumption cannot be explained reasonably by a high consumption among the 83 nonrespondents.

The prognostic effect of tobacco and alcohol consumption in intra-oral squamous cell carcinoma.

The aim of this study was to assess the potential prognostic value of tobacco and alcohol consumption in 161 consecutive patients with intra-oral squamous cell carcinoma. The patients were included in a prospective clinico-experimental and epidemiological study to secure valid data on tobacco and alcohol consumption. Univariate analysis showed that patients with an alcohol consumption above the median had a significantly (P = 0.03) poorer prognosis than other patients, with 5-year cause-specific survivals of 54 +/- 6 and 33 +/- 6%, respectively. Similarly, patients with a tobacco consumption above the median had a worse prognosis than other patients, with 5-year cause-specific survivals of 55 +/- 6 and 39 +/- 6%, respectively. This difference was on the borderline of significance, P = 0.056. Tobacco and alcohol consumption were correlated and each of them correlated with sex, males having a higher consumption than females. T-stage, N-stage, clinical stage, tumour size and sex all had a significant prognostic impact. To elucidate whether tobacco and alcohol consumption had an independent prognostic value, a multivariate analysis by means of the Cox proportional hazards regression analysis was performed. This analysis showed that clinical stage (P = 2 x 10(-5)), tumour size (P = 0.007) and tobacco consumption (P = 0.046), but not alcohol consumption, had significant influences on prognosis. Thus, smoking cessation programmes seem warranted both from a prophylactic and a therapeutic point of view.

Oral squamous cell cancer in non-users of tobacco and alcohol.

In a well-defined group of 161 consecutive patients with intra-oral squamous cell carcinoma we found 23 non-users of tobacco and alcohol. The non-users in this prospective study were compared with users of tobacco and alcohol in the study, and to a sex- and age-matched control group drawn at random from the Danish Central Citizenry Registration. The users in the patient group represented a significantly higher number than in the control group. As to non-users, women represented a higher number in the patient group compared with the control group. Among users and non-users differences were found in the location of the primary tumour and in the degree of differentiation of the tumour. Haematological status and liver function parameters were different in the two groups. There was no difference in dental or oral hygiene status or risk occupation among the groups. The stage and the course of the disease (corrected survival) showed only insignificant differences. The non-user group contained especially older women, and only one of them had anaemia.

[Functional endoscopic endonasal sinus surgery. First experiences with a new method]. / Funktionel endoskopisk endonasal bihulekirurgi. De første erfaringer med en ny metode.

A material of 46 patients who were treated operatively on account of chronic recurrent sinusitis by functional endoscopic sinus surgery by Messerklinger's method is presented. In 80% the operation was bilateral. As a serious complication, one case of dural lesion occurred. This healed without further complications and without sequelae. Just under 30% experienced slight per- or postoperative complications in the form of haemorrhage and infection. All of the patients participated in a follow-up examination after an average of 13 months' observation. 80-85% stated that they were free from symptoms or had improved after operation. Late complications were insignificant. Half of the patients had synechia formation in the resection area but the presence of synechia was not found to have any significant relationship to the postoperative course. When it is taken into consideration that the first experience with a new method is concerned, the results are considered to be satisfactory. A more extensive patient material with more prolonged observation and experience from other departments are necessary before the employability of the method in the Danish therapeutic system can be assessed.

[Acute tonsillectomy in infectious mononucleosis]. / Akut tonsillektomi ved mononucleosis infectiosa.

Enlargement of the pharyngeal tonsils in infectious mononucleosis (MI) is frequently an important component of the clinical picture but pronounced obstruction of the upper respiratory passages is rare. An analysis of 11 cases of infectious mononucleosis with varying degrees of pharyngeal obstruction is presented. During the acute phase of the disease, tonsillectomy was performed and also adenoidectomy in four of the cases. The patients improved rapidly after the operation and were discharged after an average of four days. No noteworthy complications of the operation occurred. An unexpectedly great number of cases of abscess formation were found at operation. Histological examination of the tonsils revealed changes in the lymphoid tissue which were characteristic but not specific for infectious mononucleosis together with extensive necrosis of the tonsillar surface. On the basis of this investigation, the authors consider that acute tonsillectomy is indicated in infectious mononucleosis with threatening occlusion of the upper airway and in cases of suspected peritonsillar abscess. In cases of slight or moderate respiratory obstruction, acute tonsillectomy may be considered in the therapeutic deliberations if the course of the condition is protracted and steroid treatment does not have the desired effect.

Squamous cell carcinoma of the oral cavity: a retrospective analysis of treatment and prognosis.

A retrospective study of 267 patients with an oral cavity squamous cell carcinoma is presented. It includes all patients from a geographically well-defined area during an 11 and one-quarter year period. Thirty-five percent of the patients were treated with radical surgery, 40% with curative-dosage radiotherapy and 22% with combined therapy. One-year survival with No Evidence of Disease (NED) was 48%. Almost all recurrences were within the first year following completion of the initial treatment. Treatment results were especially ineffective in large local tumour cases (T3 and T4) and in instances with extensive regional lymph node metastases (N2 and N3). The observed 5-year survival ('crude survival') was 44%. All parameters for the course of disease following diagnosis and treatment were significantly correlated to disease stage.