bluuebunny/crossref_metadata_2025 huggingface dataset:
Blood pressure response to thermoregulatory vasoconstriction during isoflurane and desflurane anesthesia
Authors: Greif R. , Laciny S. , Rajek A. , Doufas A. G. , Sessler D. I.
Published: July 2003

Background:  Mild perioperative hypothermia produces morbid cardiac outcomes that may result from sympathetically induced hypertension. However, volatile anesthetics produce vasodilatation that may reduce the hemodynamic response to hypothermia. We tested the hypothesis that the volatile anesthetics isoflurane and desflurane blunt the normal cold‐induced hypertensive response.

Methods:  We analyzed prospective data from three analogous studies: 1) 10 volunteers given desflurane (2.6 Volume percentage) maintained in left‐lateral position; 2) nine volunteers without anesthesia or anesthetized with various doses of desflurane; and 3) eight volunteers given various concentrations of isoflurane. Mean skin temperature was reduced to 31 C, which decreased core body temperature and triggered thermoregulatory vasoconstriction. Mean arterial pressures were determined before and after hypothermia provoked intense thermoregulatory vasoconstriction.

Results:  The hemodynamic responses to thermoregulatory vasoconstriction were similar without anesthesia and at all concentrations of desflurane and isoflurane. On average, mean arterial pressure increased 14 (SD = 5) mmHg with and without anesthesia.

Conclusion:  We conclude that thermoregulatory vasoconstriction significantly increases arterial pressure with or without isoflurane or desflurane anesthesia.
Pneumocephalus following an epidural blood patch
Authors: Kawamata T. , Omote K. , Matsumoto M. , Toriyabe M. , Ito T. , Namiki A.
Published: July 2003

Pneumocephalus is a rare complication of epidural block. We report a case of pneumocephalus complicating an epidural blood patch performed 3 days after unintentional dural puncture. Pneumocephalus may occur during an epidural blood patch procedure, even if the epidural needle tip is within the epidural space.
Anesthesia‐related mortality and morbidity over a 5‐year period in 2,363,038 patients in Japan
Authors: Kawashima Y. , Takahashi S. , Suzuki M. , Morita K. , Irita K. , Iwao Y. , Seo N. , Tsuzaki K. , Dohi S. , Kobayashi T. , Goto Y. , Suzuki G. , Fujii A. , Suzuki H. , Yokoyama K. , Kugimiya T.
Published: July 2003

Background:  Statistical data of mortality and morbidity related to anesthesia have not been reported in Japan since World War II. The need to comprehensively examine the events of cardiac arrest as well as mortality prompted the first national study in Japan.

Methods:  Confidential questionnaires were sent to all Japan Society of Anesthesiologists Certified Training Hospitals every year from 1994 through 1998. Collected data were analyzed for incidence of cardiac arrest and other critical events during anesthesia and surgery, and their outcomes within 7 postoperative days. The principal causes of the critical incidents were also analyzed.

Results:  With an average response rate of 39.9%, a total of 2,363,038 cases were documented over 5 years. The average incidence per year of cardiac arrest during surgery due to all etiologies and that totally attributable to anesthesia was 7.12 [95%CI: 6.30,7.94] and 1.00 [0.88, 1.12]) per 10,000 cases, respectively. The average mortality per year in the operating room or within 7 postoperative days due to all etiologies and that totally attributable to anesthesia was 7.18 [6.22, 8.13] and 0.21 [0.15, 0.27] per 10,000 cases, respectively. The two principal causes of cardiac arrest during anesthesia and surgery due to all etiologies were massive hemorrhage (31.9%) and surgery (30.2%), and those totally attributable to anesthesia were drug overdose or selection error (15.3%) and serious arrhythmia (13.9%). Preventable human errors caused 53.2% of cardiac arrest and 22.2% of deaths in the operating room totally attributable to anesthesia.

Conclusions:  The rates in Japan of cardiac arrest and death during anesthesia and surgery due to all etiologies as well as those totally attributable to anesthesia are comparable to those of other developed countries.
Aerosolized surfactant and dextran for experimental acute respiratory distress syndrome caused by acidified milk in rats
Authors: Cui XG. , Tashiro K. , Matsumoto H. , Tsubokawa Y. , Kobayashi T.
Published: July 2003

Background:  Inhibition of pulmonary surfactant by plasma‐derived proteins is an important pathogenetic factor of acute respiratory distress syndrome (ARDS). Inhalation of aerosolized surfactant may be suitable for early treatment of ARDS. However, requirement of a high dose is a drawback. Because dextran reverses surfactant inhibition, we examined whether dextran improves the therapeutic effects of aerosolized surfactant in rats with experimental ARDS.

Methods:  Acidified milk (pH 1.8, 1.5 ml kg−1) was injected into the trachea of the rats ventilated with pure oxygen using 2.45 kPa peak inspiratory pressure and 0.74 kPa positive end‐expiratory pressure. When PaO2 decreased to <13 kPa, the rats were assigned to four groups: control group (n = 8), receiving no material; D‐only group (n = 6), receiving aerosolized dextran for 45 min; S‐only group (n = 8), receiving aerosolized modified natural surfactant (MNS) for 30 min; and S‐plus‐D group (n = 9), receiving aerosolized MNS for 30 min followed by aerosolized dextran for 15 min.

Results:  In the control group and D‐only groups, the mean PaO2 remained at <10 kPa for 180 min. In the S‐only and S‐plus‐D groups, the PaO2 increased to 50 kPa (P < 0.01 vs. untreated). The PaO2 of the surfactant‐only group gradually decreased to <17 kPa at 180 min, whereas the PaO2 of the S‐plus‐D group was maintained at >38 kPa for 180 min (P < 0.01 vs. S‐only group).

Conclusion:  Inhalation of aerosolized dextran potentiates the effects of aerosolized surfactant by prolonging the therapeutic response.
Comparison of transcutaneous and endtidal CO2‐monitoring for rigid bronchoscopy during high‐frequency jet ventilation
Authors: Simon M. , Gottschall R. , Gugel M. , Fritz H. , Mohr S. , Klein U.
Published: July 2003

Objective:  To compare endtidal and transcutaneous respiratory monitoring of high‐frequency jet ventilation (HFJV) in rigid bronchoscopy. Both techniques provide a noninvasive measurement of pCO2.

Methods:  High‐frequency jet ventilation was applied via a rigid bronchoscope. Driving pressure (DP) was initially adapted to ensure normal ventilation. It was then changed twice by ±30% from the initial value. Endtidal and transcutaneous data were compared with arterial blood gas monitoring (ABG).

Results:  Results were analyzed separately for the time just after changing the driving pressure (10 min) and the remaining time until the next change of the driving pressure (4 min). The first part was called the dynamic phase, and the second part the steady‐state phase. Correlation coefficient between endtidal capnography and ABG was 0.96 for the steady state and 0.94 for the dynamic phase, respectively. Bland‐Altman analysis revealed a bias of −0.21 kPa with limits of agreement (LOA) 1.63 kPa for the steady state and −0.25 kPa, 2.08 kPa for the dynamic phase, respectively. Correlation coefficient between transcutaneous monitoring and ABG for the steady state phase was 0.83, and was 0.72 for the dynamic phase. Bland‐Altman analysis resulted in a bias of −0.89 kPa with LOA − 3.84 kPa during steady state and 0.92 kPa, 4.06 kPa for the dynamic phase, respectively.

Conclusion:  Endtidal capnography offers accurate respiratory monitoring of HFJV. Transcutaneous monitoring showed a good correlation to ABG only during steady‐state conditions. For the dynamic phase the accuracy was significantly lower. Thus, we cannot recommend transcutaneous respiratory monitoring for the specific indication of rigid bronchoscopy using HFJV.
Acupuncture fails to reduce but increases anaesthetic gas required to prevent movement in response to surgical incision
Authors: Kvorning N. , Christiansson C. , Beskow A. , Bratt O. , Åkeson J.
Published: July 2003

Background:  Acupuncture is used for clinical pain relief but has not been evaluated under clinical anaesthesia. This study was designed to compare movement in response to surgical incision in anaesthetized patients subjected to electro‐acupuncture (EA) or sham procedures. Our hypothesis was that EA stimulation would reduce the requirements for anaesthetic gas.

Methods:  Forty‐six healthy women, scheduled for laparoscopic sterilization at a Swedish county hospital, were randomized to have either the electro‐acupuncture (n = 23) or sham (n = 23) procedure between the induction of general anaesthesia and the start of surgery. The minimal alveolar concentration (MAC) of sevoflurane required to prevent neck or major limb movements in response to surgical incision was determined in each group of patients.

Results:  The MAC for sevoflurane was found to be higher in the group given acupuncture than in the control group (2.1 ± 0.3% vs. 1.8 ± 0.4%; P = 0.008).

Conclusion:  Electro‐acupuncture given during general anaesthesia with sevoflurane failed to reduce but instead increased the clinical need for anaesthetic gas, possibly by reducing the anaesthetic effect of sevoflurane and/or by facilitating nociceptive transmission and/or reflex activity.
Dexamethasone is as effective as ondansetron for the prevention of postoperative nausea and vomiting following breast surgery
Authors: Wattwil M. , Thörn S‐E. , Lövqvist Å. , Wattwil L. , Gupta A. , Liljegren G.
Published: July 2003

Introduction:  Postoperative nausea and vomiting remain a common problem following breast surgery. This study assesses whether dexamethasone is as effective as ondansetron in the control of postoperative nausea and vomiting (PONV).

Methods:  Eighty ASA I–III patients undergoing breast surgery for carcinoma of the breast were included in the study. Following premedication with diazepam 5–10 mg, patients were induced with fentanyl 50 µg and propofol 2–2.5 mg kg−1. A larynx mask was inserted and anesthesia maintained with sevoflurane in oxygen and nitrous oxide. Patients were then randomly divided into two groups: Group D (dexamethasone) was given 4 mg dexamethasone i.v. after induction and Group O (ondansetron) was given 4 mg ondansetron at the same time point. Postoperatively, nausea, vomiting and pain were recorded at 1‐h intervals during 4 h, and thereafter every 4 h during 24 h.

Results:  The incidence of PONV during 24 h was 37% and 33% in Group D and Group O, respectively (NS). No differences were found between the groups in the incidence of postoperative nausea, vomiting or pain at the different time intervals. No differences were found in the incidence of PONV in smokers vs. non‐smokers. No side‐effects of these drugs were observed.

Conclusions:  Ondansetron 4 mg or dexamethasone 4 mg are equally effective in the prevention of postoperative nausea and vomiting following breast surgery. Other factors being similar, the difference in cost between these drugs would favor the use of dexamethasone instead of ondansetron when monotherapy against PONV is used.
ACE inhibition does not exaggerate the blood pressure decrease in the early phase of spinal anaesthesia
Authors: Höhne C. , Meier L. , Boemke W. , Kaczmarczyk G.
Published: July 2003

Background:  This study investigates whether long‐term treatment with an angiotensin converting enzyme inhibitor (ACEI) impairs the hemodynamic regulation during the early phase of spinal anaesthesia.

Methods:  Forty‐two patients undergoing minor surgery were studied. Twenty‐one patients were long‐term treated (ACEI group), while the other patients served as controls (nonACEI group). All patients received a balanced electrolyte solution(6 ml kg−1) 20 min before spinal anaesthesia.

Results:  Mean arterial blood pressure decreased 19% in both groups within 20 min after spinal anaesthesia. Heart rate did not change in either group. Plasma renin concentration increased from 7.3 ± 2.1 to 12.8 ± 4 pg ml−1 during spinal anaesthesia in nonACEI patients (P < 0.05), whereas an elevated plasma renin level remained unchanged in the nonACEI group. The angiotensin II concentration increased in both groups during spinal anaesthesia (P < 0.05). The vasopressin concentration did not change during spinal anaesthesia in the ACEI group, but increased from 1.2 ± 0.3 to 2.2 ± 0.5 pg ml−1 in patients with ACEI treatment (P < 0.05). The norepinephrine concentration increased transiently 5 min after spinal anaesthesia in both groups, and returned to baseline levels within 15 min.

Conclusion:  Long‐term ACEI treatment does not further exaggerate the blood pressure decrease in the early phase of spinal anaesthesia. The increase in vasopressin concentrations in ACEI treated patients seems to be sufficient to compensate for the inhibited renin‐angiotensin system. In addition, the transient increase in plasma norepinephrine, which occurs independent of preoperative ACEI treatment, seems to be involved in blood pressure regulation during spinal anaesthesia.
Comparison of different concentrations of levobupivacaine for post‐operative epidural analgesia
Authors: Dernedde M. , Stadler M. , Bardiau F. , Boogaerts J.
Published: July 2003

Background:  The relative effects of the mass, volume and concentration of local anaesthetic solution used for epidural anaesthesia and analgesia are still under debate. Clinical studies have shown discrepancies, probably because of limited consideration of total dose.

Methods:  This prospective, randomized and blinded study evaluated the spread, the quality of post‐operative analgesia and the incidence of side‐effects of continuous thoracic epidural levobupivacaine 15 mg/h in three different concentrations: 1.5 mg/ml, 10 ml/h (n = 26), 5 mg/ml, 3 ml/h (n = 33) or 7.5 mg/ml, 2 ml/h (n = 31). The following variables were registered within 48 h: sensory block, pain scores, rescue morphine consumption, motor blockade, haemodynamics, sedation, nausea and vomiting, and patient satisfaction.

Results:  The three groups were similar with regard to demographics, quality of analgesia, morphine consumption, and satisfaction rate. The upper level of sensory block was two segments higher in the 1.5 mg/ml group. Motor blockade in the lower limbs was low in the three groups. Haemodynamic profile was more stable in the higher concentration groups compared with the 1.5 mg/ml patient group (P < 0.001). Nausea was more frequent in the 1.5 mg/ml group (P = 0.02).

Conclusion:  The same dose of levobupivacaine provides an equal quality of analgesia in low or high volume continuous thoracic epidural infusion with reduced haemodynamic instability and nausea in the low volume/high concentration groups.
Handling and environmental enrichment do not rescue learning and memory impairments in αCamKIIT286A mutant mice
Authors: Need A. C. , Giese K. P.
Published: July 2003

Environmental enrichment and postnatal handling have been shown to improve learning and memory in the Morris water maze, and to rescue impairments caused by genetic modification, age or genetic background. Mice with a targeted point mutation that prevents autophosphorylation at threonine‐286 of the α‐isoform of the Ca2+/calmodulin‐dependent kinase II have impaired hippocampus‐dependent and ‐independent strategy learning and memory in the water maze. We have investigated whether these impairments can be rescued with a combination of postnatal handling and environmental enrichment in a hybrid genetic background. Severe impairments were seen in acquisition and probe trials in both enriched and nonenriched mutants, indicating that enrichment did not rescue the learning and memory impairments. However, enrichment did rescue a specific performance deficit; enhanced floating behaviour, in the mutants. In summary, we have shown the lack of autophosphorylation of the α‐isoform of the Ca2+/calmodulin‐dependent kinase II prevents enrichment‐induced rescues of strategy learning and memory impairments. Furthermore, we have established that there are enrichment mechanisms that are independent of this autophosphorylation.
Genetic analysis of the psychomotor stimulant effect of ethanol
Authors: Downing C. , Rodd‐Henricks K. K. , Flaherty L. , Dudek B. C.
Published: July 2003

Genetic influences on the psychomotor stimulant effect of ethanol may be a key feature of abuse liability. While earlier work has shown the activational effects of ethanol to be under the influence of a relatively uncomplicated additive genetic system, preliminary data from our laboratory suggested the possibility of nonadditive genetic variance. In the present study, a full Mendelian cross was conducted to further characterize gene action and search for quantitative trait loci (QTL) influencing the psychomotor stimulant properties of ethanol. We tested 3062 mice of the six Mendelian cross genotypes (P1, P2, F1, F2, BC1 and BC2) derived from a cross between the C57BL/6J (B6) and C3H/HeJ (C3H) inbred strains of mice. On day 1, mice were injected with saline, put in a holding cage for 5 min, then placed in an activity monitor for 5 min. On day 2, mice were injected with 1.5 g/kg ethanol, and activity again monitored for 5 min. Analysis showed the expected activation in the C3H strain and little activation in the B6 strain, with no effect of sex. Biometrical genetic analysis showed a best‐fit model that included the mean (m), additive effect (a), and an epistatic parameter (i = homozygote by homozygote interaction). Analysis showed good evidence for QTL on chromosomes 1 (logarithm of odds (LOD) 3.4–7.5, 88–100 cM), 6 (LOD 9.1–10.4, 46–50 cM) and 15 (LOD 7.3–8.8, 28–32 cM). While the regions on chromosomes 1 and 6 have previously been implicated in several different ethanol‐related phenotypes, this is the first report of a QTL influencing the psychomotor stimulant properties of ethanol on chromosome 15. Other studies have identified QTL in this region of chromosome 15 mediating locomotor activation caused by other psychostimulants, including cocaine, amphetamine and phencyclidine.
Human neural stem cells: a new tool for studying cortical development in Down's syndrome
Authors: Bhattacharyya A. , Svendsen C. N.
Published: July 2003

The clinical characteristics of Down's syndrome (DS), or trisomy 21, are caused by errors that occur during development. In addition to mental retardation, DS individuals have craniofacial abnormalities, clinical defects of the heart, gut and immune system, as well as predisposition to certain diseases, such as leukemias and Alzheimer's disease. To explain the developmental mechanisms that cause these traits, it is necessary to look at how developmental processes in DS compare to normal development. The neurological characteristics of DS are established during the prenatal and early postnatal period in humans, when the bulk of brain development occurs. Mouse models of DS have provided a useful way of studying DS neural development. However, there are clearly significant differences between rodent and human biology that may not be reflected in mouse models. Recent advances in stem cell biology now allow the generation of human neural tissue in the culture dish (Ostenfeld & Svendsen 2003). Stem cells offer a novel model system to study alterations in neuron development in developmental disorders such as DS.
RAL GTPases are linchpin modulators of human tumour‐cell proliferation and survival
Authors: Chien Yuchen , White Michael A
Published: July 2003

The monomeric RAL (RAS‐like) GTPases have been indirectly implicated in mitogenic regulation and cell transformation. Here, we show that RALA and RALB collaborate to maintain tumorigenicity through regulation of both proliferation and survival. Remarkably, this task is divided between these highly homologous isoforms. RALB is specifically required for survival of tumour cells but not normal cells. RALA is dispensable for survival, but is required for anchorage‐independent proliferation. Reducing the ‘oncogenic burden’ in human tumour cells relieves the sensitivity to loss of RALB. These observations establish RAL GTPases as crucial components of the cellular machinery that are exploited by factors that drive oncogenic transformation.
Fly and mammalian lipid phosphate phosphatase isoforms differ in activity both in vitro and in vivo
Authors: Burnett Camilla , Howard Ken
Published: July 2003

Wunen (Wun), a homologue of a lipid phosphate phosphatase (LPP), has a crucial function in the migration and survival of primordial germ cells (PGCs) during Drosophila embryogenesis. Past work has indicated that the LPP isoforms may show functional redundancy in certain systems, and that they have broad‐range lipid phosphatase activities in vitro, with little apparent specificity between them. We show here that there are marked differences in biochemical activity between fly Wun and mammalian LPPs, with Wun having a narrower activity range than has been reported for the mammalian LPPs. Furthermore, although it is active on a range of substrates in vitro, mouse Lpp1 has no activity on an endogenous Drosophila germ‐cell‐specific factor in vivo. Conversely, human LPP3 is active, resulting in aberrant migration and PGC death. These results show an absolute difference in bioactivity among LPP isoforms for the first time in a model organism and may point towards an underlying signalling system that is conserved between flies and humans.
Quantification of induced resistance against Phytophthora species expressing GFP as a vital marker: β‐aminobutyric acid but not BTH protects potato and Arabidopsis from infection
Authors: Si‐Ammour Azeddine , Mauch‐Mani Brigitte , Mauch Felix
Published: July 2003

Induced resistance was studied in the model pathosystem Arabidopsis‐Phytophthora brassicae (formerly P. porri) in comparison with the agronomically important late blight disease of potato caused by Phytophthora infestans. For the quantification of disease progress, both Phytophthora species were transformed with the vector p34GFN carrying the selectable marker gene neomycine phosphotransferase (nptII) and the reporter gene green fluorescent protein (gfp). Eighty five per cent of the transformants of P. brassicae and P. infestans constitutively expressed GFP at high levels at all developmental stages both in vitro and in planta. Transformants with high GFP expression and normal in vitro growth and virulence were selected to quantify pathogen growth by measuring the in planta emitted GFP fluorescence. This non‐destructive monitoring of the infection process was applied to analyse the efficacy of two chemical inducers of disease resistance, a functional SA‐analogue, benzothiadiazole (BTH), and β‐aminobutyric acid (BABA) which is involved in priming mechanisms of unknown nature. BABA pre‐treatment (300 µm) via soil drench applied 24 h before inoculation completely protected the susceptible Arabidopsis accession Landsberg erecta (Ler) from infection with P. brassicae. A similar treatment with BTH (330 µm) did not induce resistance. Spraying the susceptible potato cultivar Bintje with BABA (1 mm) 2 days before inoculation resulted in a phenocopy of the incompatible interaction shown by the resistant potato cultivar Matilda while BTH (1.5 mm) did not protect Bintje from severe infection. Thus, in both pathosystems, the mechanisms of induced resistance appeared to be similar, suggesting that the Arabidopsis‐P. brassicae pathosystem is a promising model for the molecular analysis of induced resistance mechanisms of potato against the late blight disease.
Root‐knot nematode parasitism and host response: molecular basis of a sophisticated interaction
Authors: Abad Pierre , Favery Bruno , Rosso Marie‐Noëlle , Castagnone‐Sereno Philippe
Published: July 2003

Taxonomy: Eukaryota; Metazoa; Nematoda; Chromadorea; order Tylenchida; Tylenchoidea; Heteroderidae; genus Meloidogyne.

 Physical properties: Microscopic‐non‐segmented worms. Meloidogyne species can reproduce by apomixis, facultative meiotic parthenogenesis or obligate mitotic parthenogenesis. Obligate biotrophic parasites inducing the re‐differentiation of plant cells into specialized feeding cells.

 Hosts: Meloidogyne spp. can infest more than 3000 plant species including vegetables, fruit trees, cereals and ornamental flowers.

 Symptoms: Root swellings called galls. Alteration of the root vascular system.

 Disease control: Cultural control, chemical control, resistant cultivars.

 Agronomic importance: Major threat to agriculture in temperate and tropical regions.
Alternaria spp.: from general saprophyte to specific parasite
Authors: Thomma Bart P. H. J.
Published: July 2003

Alternaria species are mainly saprophytic fungi. However, some species have acquired pathogenic capacities collectively causing disease over a broad host range. This review summarizes the knowledge on pathogenic strategies employed by the fungus to plunder the host. Furthermore, strategies employed by potential host plants in order to ward off an attack are discussed.

Taxonomy: Alternaria spp. kingdom Fungi, subkingdom Eumycotera, phylum Fungi Imperfecti (a non‐phylogenetic or artificial phylum of fungi without known sexual stages whose members may or may not be related; taxonomy does not reflect relationships), form class Hypomycetes, Form order Moniliales, form family Dematiaceae, genus Alternaria. Some species of Alternaria are the asexual anamorph of the ascomycete Pleospora while others are speculated to be anamorphs of Leptosphaeria.

Host Range: Most Alternaria species are common saprophytes that derive energy as a result of cellulytic activity and are found in a variety of habitats as ubiquitous agents of decay. Some species are plant pathogens that cause a range of economically important diseases like stem cancer, leaf blight or leaf spot on a large variety of crops. Latent infections can occur and result in post‐harvest diseases or damping‐off in case of infected seed.

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Cross‐protection in Arabidopsis against crucifer tobamovirus Cg by an attenuated strain of the virus
Authors: Kurihara Yukio , Watanabe Yuichiro
Published: July 2003

Cross‐protection is a procedure that has been utilized to protect crops against virulent strains of viruses by pre‐treatment with closely related attenuated strains of the virus. We constructed a mutant of crucifer tobamovirus Cg, which is analogous to L11A, an attenuated strain of Tomato mosaic virus‐L (ToMV‐L). This mutant, named CgYD, caused few disease symptoms and could spread throughout Arabidopsis thaliana Col‐0 plants. Initial infection with CgYD was shown to efficiently cross‐protect against a challenge with wild‐type Cg. Thus, we have established in Arabidopsis a powerful system for investigating mechanisms of cross‐protection. Using this system, we showed that cross‐protection was not overcome, even if a higher concentration of the virion, or purified virion RNA, were used in the challenge. We also demonstrated that cross‐protection requires that the second virus be very similar in sequence to Cg, which is a characteristic of RNA silencing. However the RNA dependent RNA polymerase SDE1/SGS2 associated with post‐transcriptional gene silencing was not required for cross‐protection.
Identification of cytokinins produced by the plant parasitic nematodes Heterodera schachtii and Meloidogyne incognita
Authors: De Meutter Jan , Tytgat Tom , Witters Erwin , Gheysen Greetje , Van Onckelen Henri , Gheysen Godelieve
Published: July 2003

The presence of different types of cytokinins was analysed in exudates and lysates of stage‐2 juveniles of Heterodera schachtii and Meloidogyne incognita and in mixed stages of Caenorhabditis elegans. For all species, cytokinins were detected in lysates and exudates in which benzyladenine and zeatin‐type cytokinins were the most prominent forms. The production of cytokinins by Meloidogyne was much higher than by Heterodera, and the detected levels were in a range which interfered with the physiological activities of the host plant. The presence of 5‐methoxy‐N,N‐dimethyltryptamine hydrogen oxalate did not affect hormone production by H. schachtii, whereas resorcinol slightly stimulated hormone production by M. incognita. The exuded cytokinins may play a role in feeding site induction, more particularly in cell cycle activation and in establishing the feeding site as a nutrient sink.
Hormones and the Aging Process
Authors: Morley John E.
Published: July 2003

For more than a century, it has been suggested that failure of the secretions of the ductless glands leads to aging. Replacement of these hormones has been suggested as a method of slowing the aging process. Clearly, modern research has demonstrated that the concept of a “hormonal fountain of youth” is predominantly mythology. The best evidence for hormonal replacement is vitamin D and estrogen replacement to prevent hip fractures. Other than that, treatment should be limited to hormone replacement in persons who have endocrine disease.
The Training of Geriatricians in the United States: Three Decades of Progress
Authors: Warshaw Gregg A. , Bragg Elizabeth J.
Published: July 2003

During the past 3 decades, significant progress has been made in preparing U.S. physicians to care for the growing elderly population. This paper reviews progress in training and certifying internists and family physicians in geriatric medicine. The establishment of the National Institute on Aging, a series of Institute of Medicine reports, Veterans Health Administration initiatives, and leadership and investment by the public sector and private foundations have supported the development of geriatric medicine training programs. In 1988, the Accreditation Council for Graduate Medical Education initially accredited 62 internal medicine (IM) and 16 family practice (FP) geriatric medicine fellowship programs. By academic year 2001–2002, 120 geriatric medicine fellowships were training 338 fellows. A recent survey of U.S. medical schools found a total of 869 full‐time equivalent (FTE) geriatrics faculty members. Their geriatrics programs had a median of 5.0 FTE physician faculty members, with a range of 0 to 42. Recent surveys of IM and FP residency programs found 803 geriatrician faculty members teaching in IM residency programs (53% response rate) and 453 teaching in FP residency programs (75% response rate). From 1988 through 2002, 10,207 Certificates of Added Qualifications in Geriatrics were awarded. The distribution of these practicing geriatricians varied considerably by state, with the national average being 5.5 per 10,000 persons aged 75 and older. Individual state rates ranged from 2.2 to 15.9. Although geriatric medicine training has grown remarkably over the past 3 decades, this growth is still not producing the number of geriatricians needed to care for the growing elderly population. Thus, expanded investment in the training of geriatricians as faculty and practitioners is needed.
Quality of Care for Older Persons at the Dawn of the Third Millennium
Authors: Reuben David B. , Shekelle Paul G. , Wenger Neil S.
Published: July 2003

During the past quarter century, researchers, providers, insurers, and governmental agencies have devoted considerable effort to improving and standardizing the quality of health care provided to older persons. Because older persons differ from younger persons as a result of their life expectancy, disease prevalence and comorbidity, social resources, goals of treatment, and preferences for care, defining and measuring quality of care has been more difficult for this age group. Nevertheless, several decades of research have led to reliable, although imperfect, methods of measuring quality, including those for geriatric conditions.

Using these measurement approaches, a variety of studies using different patient populations and sampling strategies have consistently identified deficiencies in quality of care provided to older persons. Moreover, efforts to improve quality of care for older persons have been difficult to design, implement, and sustain. Some have been successful, including having effects on outcome measures, but have not made the transition from research to clinical settings. Others have used quality improvement methods to improve the care of diseases (e.g., diabetes mellitus, congestive heart failure) that commonly affect older persons. However, the lack of alignment of incentives between providers and insurers for most older persons is a major barrier to this approach. In addition, there is no concerted effort among providers, regulatory agencies, and insurers to move the quality‐of‐care agenda for most Medicare recipients. Despite substantial progress in defining and measuring high‐quality care for older persons, the goal of ensuring that older persons receiving such care remains a distant hope.
Disruption of a longitudinal pattern in environmental factors and benthic fauna by a glacial tributary
Authors: Knispel S. , Castella E.
Published: July 2003

SUMMARY 1. In the upper Rhône catchment (Swiss Alps), modifications in the longitudinal pattern of environmental conditions and the benthic macroinvertebrate fauna were investigated in a glacier‐fed stream (Rhône) at its confluence with a smaller glacier‐fed tributary (Mutt) in June, August and September 1998. The distance to the source glacier was greater for the Mutt than for the Rhône.

2. Environmental conditions were harsher for the biota in the main stream upstream of the confluence than in the tributary. The tributary upstream of the confluence was characterised by higher taxonomic richness and abundance of the zoobenthos than the Rhône upstream.

3. Although environmental conditions in the main stream were little modified by the tributary, the fauna was richer and more diverse below the confluence. During the period of ice melt, colonisation from the Mutt led to the occurrence of faunal elements atypical of glacial streams in the main glacial stream upstream of the confluence, where water temperature remains below 4 °C.

4. Although contributing an average of only 10% to the Rhône discharge, the Mutt tributary is suggested to be the faunal driver of the system.
Sources of organic carbon supporting the food web of an arid zone floodplain river
Authors: Bunn Stuart E. , Davies Peter M. , Winning Michelle
Published: July 2003

SUMMARY 1. Many Australian inland rivers are characterised by vast floodplains with a network of anastomosing channels that interconnect only during unpredictable flooding. For much of the time, however, rivers are reduced to a string of disconnected and highly turbid waterholes. Given these features, we predicted that aquatic primary production would be light‐limited and the riverine food web would be dependent on terrestrial carbon from floodplain exchanges and direct riparian inputs.

2. To test these predictions, we measured rates of benthic primary production and respiration and sampled primary sources of organic carbon and consumers for stable isotope analysis in several river waterholes at four locations in the Cooper Creek system in central Australia.

3. A conspicuous band of filamentous algae was observed along the shallow littoral zone of the larger waterholes. Despite the high turbidity, benthic gross primary production in this narrow zone was very high (1.7–3.6 g C m−2 day−1); about two orders of magnitude greater than that measured in the main channel.

4. Stable carbon isotope analysis confirmed that the band of algae was the major source of energy for aquatic consumers, ultimately supporting large populations of crustaceans and fish. Variation in the stable carbon and nitrogen isotope signatures of consumers suggested that zooplankton was the other likely major source.

5. Existing ecosystem models of large rivers often emphasise the importance of longitudinal or lateral inputs of terrestrial organic matter as a source of organic carbon for aquatic consumers. Our data suggest that, despite the presence of large amounts of terrestrial carbon, there was no evidence of it being a significant contributor to the aquatic food web in this floodplain river system.
Is water temperature an adequate predictor of recruitment success in cyprinid fish populations in lowland rivers?
Authors: Nunn A. D. , Cowx I. G. , Frear P. A. , Harvey J. P.
Published: July 2003

SUMMARY 1. Higher than average ambient water temperature in the first year of life may be responsible for strong cohorts of adult cyprinid fish. Whilst temperature explains much of the variation in year‐class strength (YCS), however, it is not the only influential factor as high temperature does not inevitably yield strong year‐classes. Furthermore, years in which a strong year‐class is prevalent in one species do not necessarily result in strong year‐classes in other coexisting species, suggesting other biotic and abiotic factors are important in regulating recruitment success.

2. The relationships between water temperature, river discharge, the position of the Gulf Stream, 0‐group fish growth and recruitment success (YCS) were examined in three cyprinid fish species in an English lowland river, using a 15‐year data set.

3. Mean length of 0‐group fish at the end of the summer was positively correlated with water temperature (cumulative degree‐days >12 °C) and negatively correlated with river discharge (cumulative discharge‐days above basal discharge rate). Water temperature was negatively correlated with river discharge.

4. YCS was positively correlated with mean 0‐group fish length at the end of the summer and with the position of the North Wall of the Gulf Stream.

5. ’Critical periods’ (i.e. periods in the first summer of life when fish may be more susceptible to increases in river discharge) were difficult to discern because of interannual variations in river discharge relative to the timing of fish hatching. YCS of roach and chub was most strongly correlated with discharge in the period from June to September inclusive, while YCS of dace was most significantly correlated with discharge in August.

6. River discharge (rather than water temperature) may be the key factor in determining YCS, either directly (through discharge‐induced mortality) or indirectly (via reduced growth at lower water temperatures, discharge‐associated increases in energy expenditure or reduced food availability). It could be that, in effect, water temperature determines potential YCS while discharge determines realised YCS.
Zooplankton responses to predation by larval bluegill: an enclosure experiment
Authors: Rettig J. E.
Published: July 2003

SUMMARY 1. Larval fish are gape‐limited predators that forage on prey of specific sizes, and thus may be expected to differentially affect members of a zooplankton community, possibly altering the size‐structure or species composition.

2. I used an enclosure experiment to look at the effect of predation by larval bluegill on the dynamics of two zooplankton communities, one dominated by large‐bodied individuals and the other by small‐bodied individuals. Enclosures containing these zooplankton received a zero, low, medium, or high density of larval bluegill predators.

3. Increasing larval density had a negative effect on zooplankton abundance and abundance declined similarly in the large‐bodied and small‐bodied communities.

4. Zooplankton size‐structure, as estimated by the length of the average zooplankton, increased and then decreased during the experiment, decreasing faster at higher larval fish densities. When zooplankton size‐structure was estimated as the length of the average cladoceran, size‐structure declined in the large‐bodied but not in the small‐bodied community and the greatest decline in size‐structure was seen in the medium and high larval density treatments.

5. Ordination of each community using multidimensional scaling (MDS) indicated that the trajectory of change in species composition differed between the presence and absence of larval fish. In both communities, the degree of response by individual taxa depended on the density of bluegill larvae. This effect on zooplankton abundance, size‐structure and community composition suggests that larval fish may make an important contribution to zooplankton dynamics in many lakes and ponds.
Do fish regulate phytoplankton in shallow eutrophic Northeast Brazilian reservoirs?
Authors: Lazzaro Xavier , Bouvy Marc , Ribeiro‐Filho Rinaldo A. , Oliviera Vanildo S. , Sales Leonardo T. , Vasconcelos André R. M. , Mata Maurício R.
Published: July 2003

SUMMARY 1. In a comparative study, we examined the potential for fish to structure planktonic food webs in shallow mesotrophic to hypereutrophic Northeast Brazilian reservoirs. The food webs were dominated by three guilds of fish (facultative piscivores, generalist planktivores and omnivores), small herbivorous zooplankton and bloom‐forming cyanobacteria, with few littoral macrophytes.

2. A principal component's analysis on data from 13 reservoirs (27 sampling dates in 1995–99) revealed that euphotic depth, the relative density of phytoplankton (i.e. the percentage of overall phytoplankton density) represented by cyanobacteria, and the relative biomass of fish (i.e. percentage of overall biomass) represented by omnivores and facultative piscivores, explained most of the variance in the data. Physico‐chemical conditions, lake morphometry and rainfall were secondary factors.

3. Phytoplankton was related to fish guild structure. Chlorophyll concentration increased with total phosphorus and the relative biomass of omnivorous fish, decreased with the relative biomass of facultative piscivores, but was unrelated to the biomass and mean body size of herbivorous zooplankton. Chlorophyll concentration and the densities of filamentous and colonial cyanobacteria decreased with the ratio of the biomass of facultative piscivores to that of omnivores (FP : OM).

4. We propose two complementary mechanisms for the observed relationships between fish and phytoplankton. At a low biomass of facultative piscivores, juvenile zooplanktivorous fishes may induce a trophic cascade on zooplankton in the littoral zone. Regardless of piscivore biomass, piscivores and omnivores may regulate phytoplankton via multichannel omnivory because of the predominance of omnivorous or detritivorous foraging behaviour.

5. Manipulative experiments are needed to explore further whether, depending on priorities in the use of the reservoir, fisheries management could alter the FP : OM ratio either to enhance fish yields or to reduce phytoplankton densities and cyanobacterial blooms.
Temperature effects on chemical signalling in a predator–prey system
Authors: Lass S. , Spaak P.
Published: July 2003

SUMMARY 1. We investigated the effect of temperature on chemical signalling in a predator–prey model system (planktivorous fish and Daphnia galeata). Life‐history changes in Daphnia in response to chemical cues (kairomones) derived from fish have become a paradigm for chemically induced anti‐predator defences.

2. As temperature can affect both predator and prey, we carried out two experiments to disentangle these effects. In order to test for temperature effects on the predator, we kept prey at a single temperature and exposed them to kairomones from fish exposed to two different temperatures. Daphnia exhibited a higher intrinsic rate of population increase (r) when exposed to fish kairomones produced at high rather than low temperature. Assuming a positive correlation between r (because of an earlier maturation and/or increased clutch sizes) and kairomone concentration, our results suggest that kairomone production increases with rising temperature.

3. In the second experiment, to study the influence of temperature on the prey, Daphnia were kept at two different temperatures and exposed to fish kairomones produced at one constant temperature. We found no interaction between the effects of fish kairomone and temperature on Daphnia life history, suggesting that temperature does not directly alter life‐history responses to fish kairomones.

4. Our results suggest that temperature influences Daphnia life history through its effects on fish kairomone concentration, but that temperature does not affect the strength of the response of Daphnia to the presence of fish.
Small‐scale patterns of genetic variation in the mayfly Bungona narilla (Ephemeroptera: Baetidae) in rainforest streams, south‐east Queensland
Authors: Hughes Jane M. , Hillyer Mia , Bunn Stuart E.
Published: July 2003

SUMMARY 1. Genetic structure of the mayfly Bungona narilla was examined using allozymes and a section of the cytochrome oxidase I gene.

2. The study had two major aims. The first was to determine whether patterns of genetic variation in mitochondrial DNA were similar to those found previously for allozymes, i.e. that more variation was evident among pools within a single stream than among streams. The mitochondrial DNA results were similar to those reported previously for allozymes, supporting the idea that larvae within any particular pool were unrepresentative of the total population and may result from a few matings.

3. The second aim was to test the hypothesis that the variation among pools within a stream was greater after dry periods than after wet periods. This was because after wet periods, larvae would have greater opportunity for mixing because of movement among pools. This hypothesis was partly supported by the mitochondrial DNA data but not by the allozyme data, in which variation among pools was extremely low on both sampling occasions. The reasons for this difference are unclear.
Relationships between picophytoplankton and environmental variables in lakes along a gradient of water colour and nutrient content
Authors: Drakare Stina , Blomqvist Peter , BergstrÖm Ann‐Kristin , Jansson Mats
Published: July 2003

SUMMARY 1. Biomass and production of picophytoplankton, phytoplankton and heterotrophic bacterioplankton were measured in seven lakes, exhibiting a broad range in water colour because of humic substances. The aim of the study was to identify environmental variables explaining the absolute and relative importance of picophytoplankton. In addition, two dystrophic lakes were fertilised with inorganic phosphorus and nitrogen, to test eventual nutrient limitation of picophytoplankton in these systems.

2. Picophytoplankton biomass and production were highest in lakes with low concentrations of dissolved organic carbon (DOC), and DOC proved the factor explaining most variation in picophytoplankton biomass and production. The relationship between picophytoplankton and lake trophy was negative, most likely because much P was bound in humic complexes. Picophytoplankton biomass decreased after the additions of P and N.

3. Compared with heterotrophic bacterioplankton, picophytoplankton were most successful at the clearwater end of the lake water colour gradient. Phytoplankton dominated over heterotrophic bacteria in the clearwater systems possibly because heterotrophic bacteria in such lakes are dependent on organic carbon produced by phytoplankton.

4. Compared with other phytoplankton, picophytoplankton did best at intermediate DOC concentrations; flagellates dominated in the humic lakes and large autotrophic phytoplankton in the clearwater lakes.

5. Picophytoplankton were not better competitors than large phytoplankton in situations when heterotrophic bacteria had access to a non‐algal carbon source. Neither did their small size lead to picophytoplankton dominance over large phytoplankton in the clearwater lakes. Possible reasons include the ability of larger phytoplankton to float or swim to reduce sedimentation losses and to acquire nutrients by phagotrophy.