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Small Doses (small + dose)
Selected AbstractsMEDICINE IN SMALL DOSESANZ JOURNAL OF SURGERY, Issue 11 2008Bruce P. Waxman No abstract is available for this article. [source] Unilateral spinal anaesthesia for outpatient surgery: a comparison between hyperbaric bupivacaine and bupivacaine,clonidine combinationACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 6 2009R. MERIVIRTA Backround: Low-dose hyperbaric bupivacaine has been used to produce unilateral spinal anaesthesia for outpatient surgery. Unilateral spinal anaesthesia is associated with reduction of hypotension, faster recovery and increased patient satisfaction. Small doses of clonidine have shown effectiveness in intensifying spinal anaesthesia. We investigated the effect of adding 15 ,g of clonidine to 5 mg hyperbaric bupivacaine on unilaterality. Methods: Sixty patients undergoing outpatient knee arthroscopy were randomly allocated to receive either 1.2 ml (6 mg) of hyperbaric bupivacaine or a 1.2 ml solution containing 1.0 ml (5 mg) hyperbaric bupivacaine, 0.1 ml (75 ,g) clonidine and 0.1 ml sterile water. The motor block was assessed by a modified Bromage scale and the sensory block by a pinprick. Results: There was a significant difference in the spread of anaesthesia between the operated and contralateral sides in both groups. Seventy-seven per cent of the blocks were unilateral in group B and 73% in group B-C. There was no significant difference between the groups, in unilaterality. The motor block was prolonged in group B-C but it did not affect home-readiness. Patients receiving clonidine needed more vasopressors. There was a significant difference in blood pressures between the groups, being lower in group B-C after 1 h 45 min. Conclusion: Using 5 mg hyperbaric bupivacaine with 15 ,g of clonidine, the unilaterality can be achieved and spinal anaesthesia intensified without affecting home-readiness. More vasopressors are needed in the beginning, but after the surgery patients experienced less pain. [source] Vasopressin in the treatment of vasodilatory shock in childrenPEDIATRICS INTERNATIONAL, Issue 2 2005Satoshi Masutani Abstract,Background:,Many recent studies suggest that vasopressin deficiency is an important cause of catecholamine-resistant hypotension with vasodilation in adults, but little is known about vasopressin deficiency in children. Methods:,To clarify the usefulness of vasopressin administration in pediatric cathecolamine-resistant hypotension with preserved ventricular contractility, urinary output and blood pressure response to vasopressin were retrospectively analyzed in 12 consecutive patients (15 instances) who were treated with vasopressin. The causes of vasodilation were central nervous system disturbance (n = 5), side-effect of drug (n = 5), and infection (n = 5). Plasma vasopressin concentration was measured six times before vasopressin administration and five times during vasopressin administration. Results:,Patients were divided into four groups according to their response to vasopressin administration. In group 1 (n = 5), urinary output increased to > 3 mL/kg per h within 3 h after vasopressin administration. In group 2 (n = 4), urinary output increased to > 3 mL/kg per h from 3 to 5 h after vasopressin administration. In group 3 (n = 4), urinary output did not increase to > 3 mL/kg per min within 5 h after vasopressin administration, but systolic blood pressure increased to > 120% of the level at the time of vasopressin administration. All remaining patients were classified into group 4 (n = 3). Plasma vasopressin concentration were low considering the markedly hypotensive state in all six instances. Plasma vasopressin concentration during vasopressin administration were significantly increased compared with before administration (P < 0.05). No apparent side-effects were observed in this series. Conclusion:,Vasopressin deficiency may occur in catecholamine-resistant hypotension of pediatric patients due to various causes including central nervous system disturbance, drug induced hypotension and sepsis. Small doses of vasopressin administration seems to be very effective in such conditions by increasing blood pressure and urinary output. [source] Small doses of methylene blue, previously considered safe, can precipitate serotonin toxicityANAESTHESIA, Issue 8 2009C. Schwiebert No abstract is available for this article. [source] PRECLINICAL STUDY: Electroacupuncture treatment reverses morphine-induced physiological changes in dopaminergic neurons within the ventral tegmental areaADDICTION BIOLOGY, Issue 4 2009Ling Hu ABSTRACT Chronic morphine administration decreases the size of dopamine (DA) neurons in the ventral tegmental area (VTA). These transient morphological changes are accompanied by a reduced sensitivity of morphine-induced conditioned place preference (CPP) after chronic exposure to the drug. In this study we examined alterations in the firing rate of DAergic neurons by means of extracellular recording following chronic morphine exposure and applied 100 Hz electroacupuncture (EA) treatment to reverse the reduced firing rate of these neurons. In the first set of experiments we show that in rats, which received chronic morphine treatment for 14 days, a small dose of morphine was not able to induce a CPP response anymore. However, the sensitivity to morphine was reinstated by consecutive EA treatment for 10 days. The electrophysiological response of VTA DA neurons to morphine was markedly reduced in chronic morphine-treated rats compared to saline-treated controls. A substantial recovery of the reactivity of VTA DA neurons to morphine was observed in rats that received 100 Hz EA for 10 days. Our findings suggest that 100 Hz EA is a potential therapy for the treatment of opiate addiction by normalizing the activity of VTA DA neurons. [source] Highly Efficient Fluorescence of NdF3/SiO2 Core/Shell Nanoparticles and the Applications for in vivo NIR Detection,ADVANCED MATERIALS, Issue 21 2008Xue-Feng Yu NdF3/SiO2 nanoparticles demonstrate highly efficient fluorescence due to successful suppressions of concentration quenching and surface quenching. More interestingly, their excitation and emission peaks with large frequency separation are both in the "near-infrared optical window" of biotissues. In living animal studies, the detecting depth can reach 1,cm by using a small dose of such nanomaterials. [source] Small-volume resuscitation: from experimental evidence to clinical routine.ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 6 2002Advantages, disadvantages of hypertonic solutions Background: The concept of small-volume resuscitatioin (SVR) using hypertonic solutions encompasses the rapid infusion of a small dose (4 ml per kg body weight, i.e. approximately 250 ml in an adult patient) of 7.2,7.5% NaCl/colloid solution. Originally, SVR was aimed for initial therapy of severe hypovolemia and shock associated with trauma. Methods: The present review focusses on the findings concerning the working mechanisms responsible for the rapid onset of the circulatory effect, the impact of the colloid component on microcirculatory resuscitation, and describes the indications for its application in the preclinical scenario as well as perioperatively and in intensive care medicine. Results: With respect to the actual data base of clinical trials SVR seems to be superior to conventional volume therapy with regard to faster normalization of microvascular perfusion during shock phases and early resumption of organ function. Particularly patients with head trauma in association with systemic hypotension appear to benefit. Besides, potential indications for this concept include cardiac and cardiovascular surgery (attenuation of reperfusion injury during declamping phase) and burn injury. The review also describes disadvantaages and potential adverse effects of SVR: Conclusion: Small-volume resuscitation by means of hypertonic NaCl/colloid solutions stands for one of the most innovative concepts for primary resuscitation from trauma and shock established in the past decade. Today the spectrum of potential indications envolves not only prehospital trauma care, but also perioperative and intensive care therapy. [source] A small dose of droperidol decreases postoperative nausea and vomiting in adults but cannot improve an already excellent patient satisfactionACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2001A. Hechler Background: We evaluated whether or not 1) a routine prophylaxis with 20 ,g ,· ,kg,1 body weight of droperidol would efficiently prevent postoperative nausea and vomiting (PONV) after elective surgery in adults and 2) an efficient prophylaxis would improve patient satisfaction. Methods: With approval of the local ethics committe and after having obtained informed written consent, 1334 patients in a randomised, single-blinded fashion either received droperidol (group 1, n=665) or saline intravenously (group 2, n=669) 20 min before the end of a standard O2/N2O/fentanyl/isoflurane anaesthesia of at least 30 min duration. End points: incidence of PONV during the first 24 h; individual episodes of nausea or vomiting, overall patient satisfaction with the procedure. Results: Compared to saline, intravenous injection of droperidol substantially and significantly reduced the incidence of PONV from 30% to 20% (P<0.0001). Women suffered three times more frequently from PONV (10.5% vs. 30%, P<0.0001). Droperidol significantly reduced the incidence of PONV from 35.4% to 24.4% in women (relative risk reduction: 31%, P=0.0002), but not in men (13.1% vs. 8.2%, relative risk reduction: 37%, P=0.159) , without impact on overall patient satisfaction (98.8% vs. 97.1%, P=0.439). Distribution of surgical procedures, sex, age, height, weight and anaesthetic duration were not different between groups. To prevent one woman from suffering PONV, nine had to be treated prophylactically at an individual drug cost (German prices) of about 0.80 per woman. Conclusion: Routine PONV prophylaxis with 20 ,g ,· ,kg,1 body weight of droperidol is cost-efficient and appropriate in women but not in men. [source] Bradycardia and asystolic cardiac arrest during spinal anaesthesia: A report of five casesACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 1 2000R. Z. Løvstad Sudden, severe bradycardia/asystolic cardiac arrest are considered infrequent, but are certainly the most serious complications of spinal anaesthesia. We report four cases of primary asystole and one of severe bradycardia in young to middle-aged, healthy patients scheduled for minor surgery at the day surgery unit. Bradycardia/asystole were not related to respiratory depression or hypoxaemia/hypercarbia; they occurred at different time intervals after the onset of spinal anaesthesia (10,70 min) and, apparently, were not dependent on the level of sensory block, which varied between T3 and T8. One patient was nauseated seconds before the asystole, otherwise there was no warning signs. All the patients were easily resuscitated with the prompt administration of atropine and ephedrine and, in the case of cardiac arrest, cardiac massage and ventilation with oxygen. One patient was treated with a small dose of adrenaline. Four patients had the surgery, as planned; one had the surgery postponed. All the patients were discharged from hospital in good health and did not suffer any sequelae. [source] Effect of an intravenous single dose of ketamine on postoperative pain in tonsillectomy patientsPEDIATRIC ANESTHESIA, Issue 9 2006MARIO JOSE DA CONCEIÇÃO MSC MD TSA Summary Background:, Tonsillectomy has a high incidence of postoperative pain. The aim of the present study was to determine whether the use of low-dose IV ketamine, before the start of surgery or after the end of the operation, would lead to significantly improved pain control after tonsillectomy in pediatric patients. Methods:, Ninety children, 5,7 years old, scheduled for elective tonsillectomy were randomly assigned to one of three groups of 30 patients each; groups I, II and III. Patients in group I received no ketamine. Patients in group II received 0.5 mg·kg,1 of ketamine before the surgical start and for group III the same dose was given after the operation ended. Postoperative pain was scored by the Oucher scale. Systolic and diastolic pressures and heart rate were recorded perioperatively. Unwanted side effects were recorded by the ward staff personnel on a 24-h study-specific questionnaire. Statistical tests consisted of Student's t -test, chi-square and anova as appropriated. Results:, The number of patients complaining of pain was greater in group I compared with patients in groups II and III with a significative statistical difference (P < 0.05). The degree of postoperative pain was significantly higher in patients of group I compared with groups II and III (P < 0.05). Eight patients in group I needed rescue doses of morphine, three for group II and none for group III. In group I, three of eight patients required two doses of morphine during the first 249h postoperatively. No unwanted side effects were noted. Conclusions:, The use of a single small dose of ketamine in a pediatric population undergoing tonsillectomy could reduce the frequency or even avoid the use of rescue analgesia in the postoperative period independent of whether used before or after the surgical procedure. [source] Protamine sulphate for treatment of severe post-reperfusion coagulopathy in pediatric liver transplantationPEDIATRIC TRANSPLANTATION, Issue 8 2009Glauber Gouvêa The ROTEM® analysis strongly suggested the presence of either a heparin effect or severe deficiency of coagulation factors. The former diagnosis was supported by a subsequent in-vitro HEPTEM. A small dose of protamine sulphate was then administered, which promptly restored hemostasis. The remainder of the procedure was uneventful. [source] Oral hypertonic glucose spray: a practical alternative for analgesia in the newbornACTA PAEDIATRICA, Issue 10 2004M Akçam Aim: Pain and stress have been shown to induce significant physiological and behavioural reactions in newborn infants. Pharmacological agents are not recommended in neonates for pain relief in minor procedures. Since different sweet solutions given orally by syringe have been shown to relieve pain in neonates, we decided to compare the analgesic effects of a small dose of glucose solution given orally by spray and by syringe during heel lancing in term neonates, using a validated behavioural acute pain rating scale. Methods: Sixty hyperbilirubinaemic full-term neonates were studied. We used a randomized, masked, placebo-controlled, crossover trial. Each infant was assessed three times receiving 0.5 ml 30% glucose in spray form, 0.5 ml 30% glucose by syringe or 0.5 ml sterile water by syringe in random order, 2 min before heel lancing. Results: Pain scores were significantly lower in the 30% glucose given either spray or syringe groups compared with the placebo group. No statistically significant difference in pain scores was found between the 30% glucose spray group and 30% glucose syringe group. Conclusions: A small dose of 0.5 ml 30% glucose spray has an equal analgesic effect to the same dose given by syringe. The spray form has the advantage of being easy to use and is well accepted by newborn babies. [source] Dietary Supplements in the Setting of Mohs SurgeryDERMATOLOGIC SURGERY, Issue 6 2002Siobhan C. Collins MD background. The use of dietary supplements has become increasingly popular. While many are safe in small doses, others may have potentially harmful effects, particularly in surgical patients. objective. To study the incidence of dietary supplement use in patients presenting for Mohs surgery. methods. One hundred consecutive patients presenting for Mohs surgery completed a questionnaire providing all current medications. During the consultation, the patients were then asked specifically about their current use of any dietary supplements. Responses differing from those on the questionnaire were recorded. results. Forty-nine of 100 patients (49%) were currently taking dietary supplements. Of this group, 17 patients (35%) self-reported the use of supplements; 32 patients (65%) did not. Thirty women (59%) were currently using dietary supplements regularly compared to 19 men (39%). Women were also more likely to self-report the use of supplements compared to men: 14 women (47%) versus three men (15%). Forty-eight of the 100 study patients (48%) were currently taking anticoagulant medications such as aspirin, warfarin, nonsteroidal anti-inflammatory drugs (NSAIDs), or clopidogrel bisulfate. Fifty instances were noted where patients were taking one or more dietary supplements that have demonstrated anticoagulant properties. Of this group, 21 instances (42%) where patients took a combination of prescription and over-the-counter (OTC) anticoagulants and one or more dietary supplements shown to have effects on coagulation were recorded. conclusion. Of the almost 50% of patients taking dietary supplements, one-third reported usage, while two-thirds did not. Women used dietary supplements more frequently than men and were more than three times more likely to offer this information. Furthermore, many supplements have been shown to have effects on coagulation, including vitamin E, garlic, ginkgo, feverfew, and fish oils. Use of these substances alone or in combination may potentiate the anticoagulant effects of each other or prescribed medications. It is therefore important for the dermatologic surgeon to communicate openly with patients regarding dietary supplements to avoid potential complications during or following surgery. [source] Effect of antipsychotic replacement with quetiapine on the symptoms and quality of life of schizophrenic patients with extrapyramidal symptomsHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 7 2006Takahide Taniguchi Abstract Replacement of antipsychotic drugs with quetiapine (QTP) was tried in a naturalistic setting in chronic schizophrenic patients who still showed moderate psychiatric symptoms and either showed extrapyramidal symptoms (EPS) or took anti-parkinson drugs for the EPS. QTP was added on and gradually increased while the previous drugs were tapered and discontinued whenever possible. Clinical symptoms, objective and subjective QOL, and EPS were measured before and 6 months after QTP addition, using Brief Psychiatric Rating Scale (BPRS), Quality of Life Scale (QLS), Schizophrenia Quality of Life Scale (SQLS) and Drug-Induced Extrapyramidal Symptom Scale (DIEPSS), respectively. Twenty-one patients completed the trial and received the assessment. It was found that replacement with QTP-improved clinical symptoms, objective and subjective QOL and EPS. This improvement was equally observed in not only patients who switched to QTP monotherapy (n,=,11) but also patients who took QTP together with reduced small doses (4.4,±,4.3,mg/day) of previous drugs (n,=,11). The results suggest that replacement with QTP improves symptoms as well as objective and subjective QOL in a subgroup of schizophrenia. Copyright © 2006 John Wiley & Sons, Ltd. [source] Homocysteine, malondialdehyde and endothelial markers in dialysis patients during low-dose folinic acid therapyJOURNAL OF INTERNAL MEDICINE, Issue 5 2002T. Apeland Abstract. Apeland T, Mansoor MA, Seljeflot I, Brønstad I, Gøransson L, Strandjord RE (Rogaland Central Hospital, Stavanger; and Ullevål University Hospital, Oslo; Norway). Homocysteine, malondialdehyde and endothelial markers in dialysis patients during low-dose folinic acid therapy. J Intern Med 2002; 252: 456,464. Objectives. Haemodialysis patients have elevated levels of the atherogenic amino acid homocysteine. We wanted to assess the effects of small doses of intravenous folinic acid (the active form of folic acid) on some biochemical risk factors of cardiovascular disease. Design. Longitudinal and open intervention study. Setting. Two dialysis units in the County of Rogaland. Subjects. All patients on maintenance haemodialysis were invited, and 32 of 35 patients gave their informed consent. Interventions. After each dialysis session, the patients were given 1.0 mg of folinic acid intravenously thrice a week for a period of 3 months. Prior to and during the study, all patients were on maintenance supplementation with small doses of vitamins B1, B2, B3, B5, B6 and B12. Main outcome measures. Changes in the levels of (i) plasma total homocysteine (p-tHcy) and folate, (ii) circulating endothelium related proteins , markers of endothelial activation and (iii) serum malondialdehyde (S-MDA) , a marker of oxidative stress and lipid peroxidation. Results. The p-tHcy levels were reduced by 37% (P < 0.0001), whilst the serum and erythrocyte folate levels increased by 95 and 104%, respectively (P < 0.0001 for both). The circulating levels of endothelium related cellular adhesion molecules and haemostatic factors remained high and unchanged, except the thrombomodulin (TM) levels increased (P = 0.0004). The high levels of S-MDA were reduced by 26% (P = 0.003). Conclusions. Low doses of folinic acid given intravenously to dialysis patients reduced their levels of p-tHcy and S-MDA and thus improved their cardiovascular risk profile. The concurrent increment in TM levels was unexpected and of unknown clinical significance. [source] The effect of amitriptyline on pain intensity and perception of stress in bruxersJOURNAL OF PROSTHODONTICS, Issue 2 2001Ariel J. Raigrodski DMD Purpose The purpose of this clinical pilot study was to evaluate the effect of a tricyclic antidepressant, amitriptyline, on pain-intensity level and level of stress in bruxers. Materials and Methods In a randomized, double-blind, crossover experimental design, 10 subjects received active (amitriptyline 25 mg/night) and inactive (placebo 25 mg/night) medication, over a period of 4 weeks. Results The administration of amitriptyline for 4 weeks did not significantly (p > .05) reduce pain intensity. However, it significantly (p < .05) reduced the level of stress perception. Conclusion The results of this limited study do not support the administration of small doses of amitriptyline over a period of 4 weeks for the management of pain resulting from sleep bruxism. However, the results support the administration of small doses of amitriptyline for the management of the perception of stress levels associated with sleep bruxism. [source] Analysis of a moving boundary value problem arising in biofilm modellingMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 15 2008Barbara Szomolay Abstract We consider a moving boundary value problem associated with a 1-D biofilm model proposed by Szomolay et al. (Environ. Microbiol. 2005; 8:1186,1191). The new model includes growth and detachment which make it more realistic in a biofilm setting. Global existence and properties of solutions are shown using the method of characteristics. We also study the existence of the corresponding steady-state solutions and prove their uniqueness for small doses of biocide. In addition, sufficient conditions for the existence of trivial/nontrivial steady states are established. Copyright © 2008 John Wiley & Sons, Ltd. [source] IR-SE and IR-MEMRI allow in vivo visualization of oscine neuroarchitecture including the main forebrain regions of the song control systemNMR IN BIOMEDICINE, Issue 1 2006Ilse Tindemans Abstract Songbirds share with humans the capacity to produce learned vocalizations (song). Recently, two major regions within the songbird's neural substrate for song learning and production; nucleus robustus arcopallii (RA) and area X (X) are visualized in vivo using Manganese Enhanced MRI (MEMRI). The aim of this study is to extend this to all main interconnected forebrain Song Control Nuclei. The ipsilateral feedback circuits allow Mn2+ to reach all main Song Control Nuclei after stereotaxic injection of very small doses of MnCl2 (10,nl of 10,mM) into HVC of one and MAN (nucleus magnocellularis nidopallii anterioris) of the other hemisphere. Application of a high resolution (80,µ) Spin Echo Inversion Recovery sequence instead of conventional T1-weighted Spin Echo images improves the image contrast dramatically such that some Song Control Nuclei, ventricles, several laminae, fibre tracts and other specific brain regions can be discerned. The combination of this contrast-rich IR-SE sequence with the transsynaptic transport property of Manganese (Inversion Recovery based MEMRI (IR-MEMRI)) enables the visualization of all main interconnected components of the Song Control System in telencephalon and thalamus. Copyright © 2006 John Wiley & Sons, Ltd. [source] Low-dose doxapram therapy for idiopathic apnea of prematurityPEDIATRICS INTERNATIONAL, Issue 2 2001Toshio Yamazaki AbstractBackground: Doxapram is contraindicated for newborn infants in Japan because of its serious side effects. However, because of encouraging results of recent studies regarding the efficacy and safety of therapy for apnea of prematurity (AOP) with lower doses of doxapram than those previously proposed, approximately 60% of Japanese neonatologists continue to use doxapram at small doses. Caution is warranted because the sample sizes of the former studies are inadequate to evaluate doxapram for both its beneficial and harmful effects. Therefore, we conducted the present study in order to investigate the efficacy and harmful events of low-dose doxapram therapy for idiopathic AOP in very low-birth weight (VLBW) infants in a larger population. Methods: One hundred and six VLBW infants with idiopathic AOP were treated with doxapram at a dose of 0.2,1.0 mg/kg per h in combination with methylxanthines and the frequency of apnea and secondary outcomes were compared with a group of control infants. Results: An approximate 80% reduction in the frequency of apnea was found with only minimal side effects following low-dose doxapram. Although there were no significant differences in secondary outcomes between the doxapram-treated and control groups, mortality in doxapram-treated infants was significantly lower than that in control infants. Conclusions: Patients with AOP unresponsive to treatment with methylxanthines may benefit from the addition of low-dose doxapram. [source] Antioxidant and hepatoprotective effects of punicalagin and punicalin on acetaminophen-induced liver damage in ratsPHYTOTHERAPY RESEARCH, Issue 3 2001Chun-Ching Lin Abstract Punicalagin and punicalin were isolated from the leaves of Terminalia catappa L., a Combretaceous plant distributed throughout tropical and subtropical beaches, which is used for the treatment of dermatitis and hepatitis. Our previous studies showed that both of these compounds exert antioxidative activity. In this study, the antihepatotoxic activity of punicalagin and punicalin on acetaminophen-induced toxicity in the rat liver was evaluated. After evaluating the changes of several biochemical functions in serum, the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were increased by acetaminophen administration and reduced by punicalagin and punicalin. Histological changes around the hepatic central vein and oxidative damage induced by acetaminophen were also recovered by both compounds. The data show that both punicalagin and punicalin exert antihepatotoxic activity, but treatment with larger doses enhanced liver damage. These results suggest that even if punicalagin and punicalin have antioxidant activity at small doses, treatment with larger doses will possibly induce some cell toxicities. Copyright © 2001 John Wiley & Sons, Ltd. [source] Pollen presentation and pollination syndromes, with special reference to PenstemonPLANT SPECIES BIOLOGY, Issue 1 2000James D. Thomson Abstract Pollen presentation theory (PPT) allows for a re-examination of some classic themes in pollination biology. Here, we outline its implications in the context of bee- and bird-adapted species of Penstemon and Keckiella (Scrophulariaceae). PPT models the optimal schedule of pollen presentation, based on the frequency of visits by pollinators, and the capacities of those pollinators to remove and deposit pollen. High visitation rates, high removal and low deposition all favor plants that present pollen in many small doses. Dosing is achieved through gradual opening of anthers and through anthers opening only narrowly. We hypothesize that bees have higher rates of removal and lower rates of deposition than birds; therefore, bee-pollinated species should have anthers that open more gradually and less completely than bird-pollinated species. Before presenting preliminary results that affirm this prediction, we critically discuss the characterization of species by pollination syndrome. PPT sheds new light on why plants may specialize on particular pollinators. Stebbins' most effective pollinator can be recast as the pollinator that deposits more of the pollen that it removes, thereby making other visitors into conditional parasites. Pollinator shifts might occur when a pollinator with low removal and high deposition becomes abundant; the plants would then be selected to discourage their previous pollinators who are now parasites. Bird-pollination may favor anthers that open quickly and widely, thereby making bees wasteful parasites. Bee-pollination may favor anthers that open slowly and narrowly, thereby making birds ineffective pollinators. In paired comparisons of closely related species, the hummingbird-visited species were redder, had narrower or longer floral tubes, more exserted anthers and stigmas, less pronounced landing platforms, more inclined orientation, produced more nectar of a lower concentration, and had anthers that dehisce faster and more extensively. [source] Medicine in small dosesANZ JOURNAL OF SURGERY, Issue 9 2010Bruce P. Waxman FRACS No abstract is available for this article. [source] Medicine in small dosesANZ JOURNAL OF SURGERY, Issue 7-8 2010Bruce P. Waxman FRACS No abstract is available for this article. [source] Medicine in small dosesANZ JOURNAL OF SURGERY, Issue 6 2010Bruce Waxman FRACS No abstract is available for this article. [source] Medicine in small dosesANZ JOURNAL OF SURGERY, Issue 5 2010Bruce P. Waxman FRACS No abstract is available for this article. [source] Medicine in small dosesANZ JOURNAL OF SURGERY, Issue 4 2010Bruce Waxman FRACS No abstract is available for this article. [source] Medicine in small dosesANZ JOURNAL OF SURGERY, Issue 3 2010Bruce Waxman FRACS No abstract is available for this article. [source] Medicine in small dosesANZ JOURNAL OF SURGERY, Issue 1-2 2010Bruce P. Waxman FRACS No abstract is available for this article. [source] Medicine in small dosesANZ JOURNAL OF SURGERY, Issue 11 2009Bruce P. Waxman FRACS No abstract is available for this article. [source] Medicine in small dosesANZ JOURNAL OF SURGERY, Issue 10 2009Bruce Waxman No abstract is available for this article. [source] | ||||||||||||||||||||||||||||