A higher-level classification of the Pannonian and western Pontic steppe grasslands (Central and Eastern Europe)

QUESTIONS

What are the main floristic patterns in the Pannonian and western Pontic steppe grasslands? What are the diagnostic species of the major subdivisions of the class Festuco-Brometea (temperate Euro-Siberian dry and semi-dry grasslands)?

LOCATION

Carpathian Basin (E Austria, SE Czech Republic, Slovakia, Hungary, Romania, Slovenia, N Croatia and N Serbia), Ukraine, S Poland and the Bryansk region of W Russia.

METHODS

We applied a geographically stratified resampling to a large set of relevés containing at least one indicator species of steppe grasslands. The resulting data set of 17 993 relevés was classified using the TWINSPAN algorithm. We identified groups of clusters that corresponded to the class Festuco-Brometea. After excluding relevés not belonging to our target class, we applied a consensus of three fidelity measures, also taking into account external knowledge, to establish the diagnostic species of the orders of the class. The original TWINSPAN divisions were revised on the basis of these diagnostic species.

RESULTS

The TWINSPAN classification revealed soil moisture as the most important environmental factor. Eight out of 16 TWINSPAN groups corresponded to Festuco-Brometea. A total of 80, 32 and 58 species were accepted as diagnostic for the orders Brometalia erecti, Festucetalia valesiacae and Stipo-Festucetalia pallentis, respectively. In the further subdivision of the orders, soil conditions, geographic distribution and altitude could be identified as factors driving the major floristic patterns.

CONCLUSIONS

We propose the following classification of the Festuco-Brometea in our study area: (1) Brometalia erecti (semi-dry grasslands) with Scabioso ochroleucae-Poion angustifoliae (steppe meadows of the forest zone of E Europe) and Cirsio-Brachypodion pinnati (meadow steppes on deep soils in the forest-steppe zone of E Central and E Europe); (2) Festucetalia valesiacae (grass steppes) with Festucion valesiacae (grass steppes on less developed soils in the forest-steppe zone of E Central and E Europe) and Stipion lessingianae (grass steppes in the steppe zone); (3) Stipo-Festucetalia pallentis (rocky steppes) with Asplenio septentrionalis-Festucion pallentis (rocky steppes on siliceous and intermediate soils), Bromo-Festucion pallentis (thermophilous rocky steppes on calcareous soils), Diantho-Seslerion (dealpine Sesleria caerulea grasslands of the Western Carpathians) and Seslerion rigidae (dealpine Sesleria rigida grasslands of the Romanian Carpathians).

Pulse carboxyhemoglobin-oximetry and cigarette smoking

PURPOSE

We used a pulse carbon monoxide (CO)-oximeter to measure the levels of carboxyhemoglobin (COHb) in smokers and non-smokers. Our goal was to determine if this device could not only define smoking status, but also to increase accuracy of self-reported data at various surveys on smoking.

METHODS

Thirty-four healthy volunteers participated in this study. Twenty-two of them were current daily smokers; 12 participants were non-smokers who lived alone or with a nonsmoker, and who worked in non-smoking environment. Nicotine dependency level was determined by the modified Fagerstrom questionnaire. Blood COHb levels were measured with a pulse CO-oximeter (Masimo, Radical 7).

RESULTS

The COHb levels in both moderate/heavy smokers and light smokers increased significantly after they smoked a single cigarette. This increase persisted for more than 6 h in the moderate/heavy smokers, while in the light smokers COHb levels returned to the baseline level after one hour. The pulse rate of all smokers increased significantly 20 min after smoking.

CONCLUSION

We conclude that the CO-oximeter can detect smoking by moderate/heavy smokers and light smokers if they smoked 6 h or 20 min earlier, respectively. We concluded that it could be used as a validation test for smoking at the time of admission to the surgical facility and to increase smoking abstinence during preoperative and postoperative periods. This noninvasive, simple and inexpensive test may also be used at various surveys to increase accuracy of self-reports on smoking.

Statistical presentation of data in biomedical publications

Scientists rely upon statistics to report their findings accurately and to interpret the published findings of others. The proper application of this discipline provides confidence in statements based upon experimental results. Professional statisticians may help at some phases of planning experiments even before results are obtained, but not all scientists avail themselves of such services. As a result, errors can occur in presentation of variability of data, and more often than not, such errors are ultimately published in biomedical journals. This paper examines the most common descriptive statistics for quantitative and categorical data. Standard deviation (SD), standard error of the mean (SEM), confidence intervals (CI), and various technical details, including how to present data in publications, and when to use particular statistical tools, are discussed as well.

Comparative study of antioxidant properties of wild growing and cultivated Allium species

Allium species are cultivated for the edible bulb, which is used mainly as flavoring in foods. Besides that, they could prevent tumor promotion and some processes that are associated with free radicals, such as cardiovascular diseases and aging. Therefore, different Allium species, both cultivated (Allium nutans L., A. fistulosum L., A. vineale L., A. pskemense B. Fedtsch, A. schoenoprasum L., A. cepa L. and A. sativum L.) and wild (A. flavum L., A. sphaerocephalum L., A. atroviolaceum Boiss, A. vineale L., A. ursinum L., A. scorodoprasum L., A. roseum L. and A. subhirsutum L.), were investigated in order to evaluate the antioxidant properties of their bulbs. This study reports on the results obtained for the bulb antioxidant enzyme activities (superoxide dismutase, catalase, guaiacol peroxidase, glutathione peroxidase), the quantities of non-enzymatic plant antioxidants (reduced glutathione and total flavonoids), the contents of soluble proteins, vitamin C, carotenoids, chlorophylls a and b, as well as for the quantities of malonyldialdehyde and .OH and O2.- radicals.

The influence of the American environment on cigarette smoking among the immigrants from the former Yugoslavia

PURPOSE

We tested the hypothesis that the American environment influences the immigrants from developing countries with high incidence of smokers to quit smoking.

METHODS

The sample included 218 immigrants who came as adults from the former Yugoslavia. A total of 275 persons were randomly selected, and the overall study response was 79.2%. The survey included questions about current smoking, smoking history, and demographic data, such as year of immigration to the USA, education, and employment status.

RESULTS

Upon their arrival, 34.8% of the adult Yugoslav immigrants were smokers; now 20.2% of these immigrants smoke(p<0.001). Smoking prevalence for women was 9.1% higher than for men. The number of cigarettes that men and women smoke per day was similar.

CONCLUSION

For an immigrant smoker, the best chance of quitting smoking was within 5 years of acculturation. The local media in their languages may provide the best health education to immigrants, including information on the effects of cigarette smoking. To reduce smoking prevalence in the former Yugoslav republics and other developing countries, rigorous antismoking measures may effectively reduce smoking prevalence and contribute to better health of their citizens.

Metabolism of angiotensin I by guinea pig aqueous humor

We investigated the degradation of angiotensin I (Ang I) by guinea pig aqueous humor at physiological pH (pH 7.4) and assessed the activity of responsible enzymes using various enzyme inhibitors. The aqueous humor was incubated with Ang I in the presence or absence of an enzyme inhibitor at 37 degrees C for the appropriate time period. The resulting peptides were analyzed by a Beckman HPLC system with a Waters microBondapak C18 analytical column using a 30-min increasing linear gradient of 10 to 40% acetonitrile containing 0.05% trifluoroacetic acid (TFA) and H2O containing 0.05% TFA at a flow rate of 1 mL/min. Detection was done by absorbance at 214 nm. Angiotensin II (Ang II) was a major product (39.3+/-4.10 nmol x h(-1) mL(-1), n = 5) of Ang I hydrolysis. Traces of angiotensin 1-9, angiotensin IV, and angiotensin 1-7 were also produced. Chymostatin (0.05 mmol/L), EDTA (1 mmol/L), enalaprilat (0.1 mmol/L), and ebelacton B (0.01 mmol/L) inhibited generation of Ang II from Ang I by guinea pig aqueous humor by 89+/-4.6, 56+/-7.6, 33+/-5.1, 20+/-6.5%, respectively. Our findings indicate that guinea pig aqueous humor contains several enzymes that can form Ang II. The chymostatin-sensitive type of enzyme was the most active one found in guinea pig aqueous humor. Angiotensin I converting enzyme, carboxypeptidase A, and deamidase may also contribute to angiotensin II formation in guinea pig ocular fluid.

Potentiation of the effects of bradykinin on its receptor in the isolated guinea pig ileum

Angiotensin I-converting enzyme (ACE/kininase II) inhibitors potentiated guinea pig ileum's isotonic contractions to bradykinin (BK) and its analogues, shifting the BK dose-response curve to the left. ACE inhibitors added at the peak of the contraction immediately enhanced it further (343 +/- 40%), although the ileum inactivated BK slowly (t(1/2) = 12-16 min). Chymotrypsin and cathepsin G also augmented the activity of BK up to three- or four-fold, but in a manner slower than that of ACE inhibitors. The BK B(2) receptor blocker HOE 140 inhibited all effects. Histamine and angiotensin II were not potentiated. ACE inhibitors potentiate BK independent of blocking its inactivation by inducing crosstalk between ACE and the BK B(2) receptor; proteases activate the receptor by different mechanism.

Doctors and smoking

The objective of this paper is to present cigarette smoking as the greatest risk factor for premature death, the nature of smoking dependence, the methods for its cessation, and to establish the importance of the leadership of health care providers in smoking prevention. Because smoking as a risk factor is preventable, it is necessary to conduct rigorous preventive measures, including educational programs and various legal actions, such as restrictions on the purchase of tobacco products to teenagers and creation of smoke-free areas. Reduction in the prevalence of smoking among physicians and other health care professionals also significantly influences willingness of society to recognize the health consequences of smoking and perhaps lead to the decline of the smoking epidemic. Therefore, a special attempt should be made to reduce smoking among health professionals, including medical students. An effort of medical students in Yugoslavia to promote prevention of smoking in the public by introducing "January 31st--A Day Without a Cigarette" is described. The best way to discourage smoking is by approaching children and adolescents since most people start smoking in their teenage years. This age group must recognize the harmful effects of smoking. Banning advertising and other promotional activities of tobacco producers, as well as smoking in hospitals, workplaces, restaurants, and public transportation is a very strong weapon against smoking.

Wall stress-induced dysrhythmias in the isolated working rat heart perfused through a cannula placed in the left ventricle via aorta

The purpose of the present study was to determine if our recently introduced novel working rat heart preparation could be used to study wall stress-induced dysrhythmias. A double cannula, which consisted of an outer cannula that, was inserted in the aorta and an inner cannula that was advanced into the left ventricle was used. The perfusion flowed through the inner cannula into the left ventricle and was ejected from there into the aorta. Afterload was changed suddenly from 60 to 160 Hg of pressure by turning a valve so that the fluid was diverted to a column set at a different height. A sudden increase of aortic pressure that lasted for 10 sec caused cardiac ectopic beats. Wall stress-induced dysrhythmias were more sustained during perfusion with low potassium and low magnesium Krebs-Henseleit solution. Bradykinin (1 microg) or epinephrine (10 microg) was injected as a bolus via an in-line injection port placed at the inner cannula. Bradykinin significantly reduced the incidence of ectopic beats and epinephrine increased the incidence of nonsustained runs of VT. This "working" heart preparation is a convenient tool to study wall stress-induced dysrhythmias.

[Drugs in the physician's bag for emergency conditions]

The list of drugs for the physician's bag depends on several factors, including practice location, conditions most likely to be found, costs and availability of drugs, organization of the emergency medicine in the region, shelf life and climatic vulnerability of certain drugs, population age, and size and design of the bag. Most of the drugs carried should be in an injectable form. However, the non-injectable drugs with relatively rapid systemic onset may be also included. Separation of drugs in the bag according to their usage may help in providing an organized treatment. For example, one could separate drugs for treatment of the following emergencies: cardiovascular, altered mental status, respiratory, gastrointestinal, bleeding, infections, and toxicological emergencies. The list of drugs needed for medical emergencies when physician makes house-calls is presented with short notes on their usage. Oncologic, toxicologic and pediatric emergencies are commented.

Attenuation of epinephrine-induced dysrhythmias by bradykinin: role of nitric oxide and prostaglandins

Cardiac dysrhythmias are common during anesthesia and surgery. An important precipitating factor of clinically relevant arrhythmias is the introoperative use of epinephrine. Bradykinin acts as an endogenous cardioprotective substance because it suppresses ventricular dysrhythmias induced by ischemia. In this study, we investigated whether bradykinin has a protective effect, preventing the development of dysrhythmias after epinephrine infusion in rats. Because kinins are potent stimulators of the release of nitric oxide and prostaglandins from the endothelium, we investigated whether the protective effect of bradykinin is mediated by these 2 autacoids. Male Sprague-Dawley rats anesthetized with sodium pentobarbital had catheters placed into a carotid artery and both jugular veins. Arterial blood pressure and lead II of the electrocardiogram (ECG) were continuously monitored and recorded. After a steady state was achieved, 1 mg/kg enalapril, an inhibitor of angiotensin I-converting enzyme/kininase II, was given intravenously to all groups except the one treated with losartan. Bradykinin was infused at the initial rate of 0.5 microg/kg per min. Cardiac arrhythmia was induced with 7.5 microg/kg epinephrine intravenously. Dysrhythmia was assessed by counting the number of premature ventricular contractions (PVCs), runs of ventricular tachycardia (V Tach), and missing beats during the first minute after epinephrine. In untreated, control rats, epinephrine caused 10.8 +/- 2.7 PVCs, 0.8 +/- 0.2 runs of V tach, and 11.6 +/- 7.4 missing beats/min. In rats pretreated with bradykinin, the same dose of epinephrine elicited 1.2 +/- 0.5 PVCs, no runs of V tach, and 0.4 +/- 0.4 missing beats/min. This beneficial effect of bradykinin was partially reversed by N-nitro-L-arginine methyl ester (L-NAME) or indomethacin, and completely by L-NAME plus indomethacin or icatibant, but it was not affected by des-Arg9[Leu8]-bradykinin. We conclude that bradykinin, acting on the B2 receptor, attenuates epinephrine-induced dysrhythmia via a mechanism that involves the release of NO and prostaglandins. Although the mechanism is not clear, NO and prostaglandins may prevent epinephrine-induced dysrhythmia and protect the myocardium via a direct action on cardiac neurons.

Removal of Arg141 from the alpha chain of human hemoglobin by carboxypeptidases N and M

Both human plasma carboxypeptidase N (CPN) and membrane-bound carboxypeptidase M (CPM) released the C-terminal arginine (alpha-Arg141) of the alpha chain of human adult hemoglobin. An arginase contamination present in the hemoglobin preparation, which converted the released arginine to ornithine, was removed by gel filtration. CPM was about 20 times more efficient than CPN or its active subunit in hydrolyzing oxyhemoglobin and cleaved oxyhemoglobin twice as fast as deoxyhemoglobin. The hydrolysis of the peptide bond of alpha-Arg141 accelerated the dissociation rate of the tetramer deoxy-des-alpha-Arg141 hemoglobin to dimers 2500-fold over that of deoxyhemoglobin, as measured by haptoglobin binding. Moreover, the dissociation of the deoxy-des-alpha-Arg141 hemoglobin tetramer to dimers was not affected by 2,3-diphosphoglyceric acid. Des-alpha-Arg141 hemoglobin had a higher oxygen affinity (P50, 5.51 mm Hg; control, 19.94 mm Hg [P50 is the partial pressure of oxygen that gives 50% of the saturation of hemoglobin]) and a lower apparent cooperativity (Hill coefficient: n, 1.02; control, 2.24) than unhydrolyzed hemoglobin. After hemoglobin was incubated in human plasma, its oxygen-binding parameters, the P50, and the Hill coefficient decreased drastically due to cleavage by CPN. In the perfused rat heart, des-alpha-Arg141 hemoglobin was a more effective coronary vasoconstrictor than hemoglobin, possibly because it dissociated to dimers in the coronary vascular bed. A covalently cross-linked hemoglobin was less active than native hemoglobin. The coronary vasoconstriction was caused by multiple factors, including interference with vasodilation by nitric oxide and eicosanoids. Thus, the hydrolysis of hemoglobin by CPM and CPN demonstrated the contribution of the alpha-Arg141 residue to sustaining the tetrameric structure of hemoglobin and its normal oxygen affinity and vasoactivity.

The isolated perfused "working" rat heart: a new method

This paper presents a "working" isolated perfused rat heart. A special double cannula was designed consisting of an outer cannula that is inserted in the aorta and an inner cannula that is advanced into the left ventricle. The perfusion fluid flows through the inner cannula into the left ventricle, and is ejected from there into the aorta. If the outer cannula system is closed, the fluid perfuses the coronary vessels and drips off outside the heart. When the outer cannula is open and certain pressure resistance is applied, a fraction of the ejected fluid perfuses coronary vessels and the rest is expelled. Because the inner cannula can easily be retracted into the outer cannula, which is placed in the aorta, this preparation provides an opportunity to use the same heart as a "working" or "non-working" model for investigating functions of the heart. The effects of epinephrine and yohimbine were tested on this model. This preparation is simple, durable, and reliable.

Mechanism of epinephrine-induced dysrhythmias in rat involves local cholinergic activation

Alterations of autonomic tone can induce cardiac dysrhythmias. In the present experiments intravenous administration of epinephrine (15 micrograms/kg) caused dysrhythmias in rat hearts. Bilateral vagotomy or yohimbine treatment did not suppress the dysrhythmic effects of epinephrine. Atropine, glycopyrrolate, and pertussis toxin reduced the number of premature ventricular contractions and eliminated missed beats caused by epinephrine. Neostigmine increased the number of missed beats but did not change the number of premature ventricular contractions. These results indicate that epinephrine induces cardiac dysrhythmias in part by local release of acetylcholine. Muscarinic receptors and pertussis toxin sensitive G proteins are involved in epinephrine-induced arrhythmogenesis.

Substance P inactivation by aqueous humor

Degradation of substance P was studied in dog and rabbit aqueous humor. Substance P inactivation was followed by the bioassay using the isolated guinea pig ileum. Both rabbit and dog aqueous humor inactivated substance P. Rabbit aqueous humor inactivated the peptide faster than dog aqueous humor. Inactivation of substance P by rabbit aqueous humor was inhibited by diisopropylfluorophosphate while other enzyme inhibitors tested (captopril, phosphoramidon, mersalyl acid and p-chloromercuriphenyl-sulphonate) were practically ineffective or had a partial inhibitory effect. Our results suggest that serine proteases, rather than other peptidases, play a major role in the inactivation of substance P in aqueous humor.

Metabolism of bradykinin by peptidases in the lung

We investigated the release of carboxypeptidase M (CPM), neutral endopeptidase 24.11 (enkephalinase, NEP), and angiotensin I converting enzyme (kininase II, ACE) and their contribution to bradykinin metabolism in the rat lung. The P3, membrane-enriched fraction of the homogenized lung was rich in all three peptidases. The activities of CPM and NEP were high in bronchoalveolar lavage fluid but lower in alveolar macrophages indicating that they originate from other cells present on the alveolar surface. In situ perfusion of rat lung with buffer that contained either deoxycholate or melittin or compound 48/80, produced lung edema. CPM, NEP, and ACE activities were recovered both in edema and perfusate fluid. The level of CPM and NEP was higher in edema fluid whereas, in contrast, more ACE activity was released into the perfusate. To evaluate the effect of peptidase inhibitors on changes in vascular permeability induced by bradykinin in the in situ perfused rat lung we measured the increase in lung weight as an index of increased vascular permeability or edema. Combined inhibition of either ACE plus NEP or ACE plus CPM augmented the effect of a subthreshold dose of bradykinin. Inhibitors of ACE, NEP, or CPM given alone and a combination of NEP plus CPM inhibitors did not enhance the bradykinin effect. Our results indicate that CPM, NEP, and ACE although present on different lung cells, synergistically modulate bradykinin effects. The different ratios of distribution of these enzymes in the perfusate and in edema fluid may not be due only to their presence on different pulmonary cells but also to their different anchoring mechanisms to plasma membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

A simple spectrophotometric method for estimation of plasma angiotensin I converting enzyme activity

The procedure described is rapid, fairly simple, and inexpensive. The method may easily be used even in a small clinical laboratory. This method, based on a specific reaction which gives a product, hippuric acid azlactone, which absorbs in the visible region, avoids the interference of reagents and solvents encountered in the UV spectrophotometric assay, in which hippuric acid is determined directly.

The effect of oxotremorine on the "free" and "bound" brain acetylcholine concentrations and motor activity in beri-beri pigeons

Oxotremorine (0.125 mg/kg i.v.) did not produce a significant change in the "free" and "bound" brain acetylcholine in beri-beri pigeons, while in normal pigeons a significant increase was obtained. Oxotremorine caused tremor in normal pigeons. In beri-beri pigeons oxotremorine did not induce tremor but the compound potentiated beri-beri symptoms (opisthotonus and convulsions).

Effect of oxotremorine on the acetylcholine content of whole brain and various brain regions in the pigeon

Oxotremorine (0.125 mg/kg) produces a significant increase in total acetylcholine content in whole pigeon brain. The contribution of different regions to this increase varies. The largest increase occurs in the nucleus basalis (paleostriatum augmentatum), a region which is highly involved in motor control. The mechanism by which oxotremorine increases the acetylcholine content of brain and the causal relationship between the rise in acetylcholine content and tremor are discussed.