bluuebunny/crossref_metadata_2025 huggingface dataset:
Time domain, geometrical and frequency domain analysis of cardiac vagal outflow: effects of various respiratory patterns
Authors: Penttilä Jani , Helminen Antti , Jartti Tuomas , Kuusela Tom , Huikuri Heikki V. , Tulppo Mikko P. , Coffeng René , Scheinin Harry
Published: March 2003

The purpose of this study was to compare the applicability of four different measures of heart rate variability (HRV) in the assessment of cardiac vagal outflow, with special reference to the effect of breathing pattern. The anticholinergic effects of an intravenous glycopyrrolate infusion (5 μg kg−1 h−1 for 2 h) during spontaneous and controlled (15 min−1) breathing rate were investigated in eight volunteers, and the effects of different fixed breathing rates (6–15–24 min–1) and hyperventilation in 12 subjects. Cardiac vagal activity was assessed by ECG recordings in which the following measures of HRV were computed: the high‐frequency (HF) spectral component, the instantaneous RR interval (RRI) variability (SD1) analysed from the Poincaré plots, the percentage of differences between successive RRIs greater than 50 ms (pNN50), and the square root of the mean squared differences of successive RRIs (RMSSD). On average, glycopyrrolate reduced the HF spectral component by 99·8%, SD1 by 91·3%, pNN50 by 100% and RMSSD by 97·0%. The change of breathing pattern from controlled to spontaneous decreased significantly the HF component and pNN50, but did not affect SD1 or RMSSD. Rapid breathing rate (24 min–1) decreased the HF component, but had no effects on the other measures. A controlled breathing rate is needed for a reliable assessment of cardiac vagal outflow by the spectral analysis technique. The quantitative geometrical analysis of short‐term RRI variability from the Poincaré plots and the time domain measure RMSSD were not significantly affected by changes in the breathing rate, suggesting that these indices are more suitable for the measurement of cardiac vagal outflow during the ‘free‐running’ ambulatory conditions.
Effects of pharmacological adrenergic and vagal modulation on fractal heart rate dynamics
Authors: Tulppo Mikko P. , Mäkikallio Timo H. , Seppänen Tapio , Shoemaker Kevin , Tutungi Elli , Hughson Richard L. , Huikuri Heikki V.
Published: March 2003

Breakdown of short‐term fractal‐like behaviour of HR indicates an increased risk for adverse cardiovascular events and mortality, but the pathophysiological background for altered fractal HR dynamics is not known. Our aim was to study the effects of pharmacological modulation of autonomic function on fractal correlation properties of heart rate (HR) variability in healthy subjects. Short‐term fractal scaling exponent (α1) along with spectral components of HR variability were analysed during the following pharmacological interventions in healthy subjects: (i) noradrenaline (NE) infusion (n=22), (ii) NE infusion after phentolamine (PHE) (n=8), (iii) combined NE + adrenaline (EPI) infusion (n=12), (iv) vagal blockade with high dose of atropine (n=10), (v) and vagal activation by low dose of atropine (n=10). Then α1 decreased progressively during the incremental doses of NE (from 0·85 ± 0·250 to 0.55 ± 0·23, P<0·0001). NE also decreased the average HR (P<0·001) and increased the high frequency spectral power (P<0·001). Vagal blockade with atropine increased the α1 value (from 0·82 ± 0·22 to 1·24 ± 0·41, P<0·05). Combined NE + EPI infusion and vagal activation with a low dose atropine did not result in any changes in α1, and α‐adrenergic blockade by PHE did not completely reverse the effects of NE on α1. Increased levels of circulating NE result in reduction of short‐term correlation properties of HR dynamics. The results suggest that coactivation of cardiac vagal outflow at the time of high levels of a circulating sympathetic transmitter explains the breakdown of fractal‐like behaviour of human HR dynamics.
An integrated model of the human ventilatory control system: the response to hypercapnia
Authors: Ursino Mauro , Magosso Elisa , Avanzolini Guido
Published: March 2003

This work presents a mathematical model of the human respiratory control system, based on physiological knowledge. It includes three compartments for gas storage and exchange (lungs, brain tissue and other body tissues), and various kinds of feedback mechanisms. These comprehend peripheral chemoreceptors in the carotid body, central chemoreceptors in the medulla and a central ventilatory depression. The latter acts by reducing the response of the central neural system to the afferent peripheral chemoreceptor activity during prolonged hypoxia of the brain tissue. Furthermore, the model considers local blood flow adjustments in response to O2 and CO2 arterial pressure changes. In this study, the model has been validated by simulating the response to square changes in alveolar PCO2, performed at different constant levels of alveolar PO2. A good agreement with data reported in the literature has been checked. Subsequently, a sensitivity analysis on the role of the main feedback mechanisms on ventilation response to CO2 has been performed. The results suggest that the ventilatory response to CO2 challenges during hyperoxia can be almost completely ascribed to the central chemoreflex, while, during normoxia, the peripheral chemoreceptors provide a modest contribution too. By contrast, the response to hypercapnic stimuli during hypoxia involves a complex superimposition among different factors with disparate dynamics. Hence, results suggest that the ventilatory response to hypercapnia during hypoxia is more complex than that provided by simple empirical models, and that discrimination between the central and peripheral components based on time constants may be misleading.
The effect of three electrotherapeutic modalities upon peripheral nerve conduction and mechanical pain threshold
Authors: Alves‐Guerreiro J. , Noble J. G. , Lowe A. S. , Walsh D. M.
Published: March 2003

The current study was designed to examine the neurophysiological and hypoalgesic effects of three types of electrical stimulation. Following approval by the University’s Research Ethical Committee, healthy volunteers (n=40; 20 males and 20 females; age 20–40 years; mean age 26·18 years) were recruited and screened for contraindications. Subjects were randomly allocated in equal numbers to the following groups: control, transcutaneous electrical nerve stimulation (TENS; 150 Hz, 125 μs), interferential therapy (IFT; 150 Hz, 125 μs) or action potential stimulation therapy (APS; 153 Hz, 6·4 ms). All treatments were applied under double‐blind conditions for 15 min over the course of the median nerve in the subject’s right forearm. Antidromic median nerve compound action potentials (CAPs) were recorded pretreatment, immediately post‐treatment (i.e. at 15 min) and then at 25, 35 and 45 min. Immediately following CAP recording, mechanical pain threshold (MPT) was recorded from two sites on the palmar surface of the right hand. Statistical analysis showed significant differences between groups for peak to peak amplitude (PPA) at 25, 35 and 45 min (Kruskal–Wallis: P=0·01, 0·01 and 0·02). Mann–Whitney U‐tests indicated a significant increase in PPA in the IFT group compared with all other groups at 25 and 35 min and compared with the TENS and APS groups at 45 min. No significant differences were found for the MPT data. This study has therefore demonstrated that none of the aforementioned modalities produced a significant hypoalgesic effect; however, IFT produced a significant change in PPA compared with TENS and APS.
NADH/NADPH oxidase p22 phox C242T polymorphism and lipid peroxidation in coronary artery disease
Authors: Stanger O. , Renner W. , Khoschsorur G. , Rigler B. , Wascher T. C.
Published: March 2003

The nicotinamide adenine dinucleotide (NADH)/nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system is a major source of superoxide anion (·O2–) production in the human vasculature and may therefore influence lipid peroxidation and severity of atherosclerosis. This study aimed to investigate a hypothetical influence of the p22 phox C242T polymorphism on the generation of malondialdehyde (MDA), extent and clinical onset of coronary artery disease (CAD) in patients. We studied 108 male Caucasians with angiographically documented CAD and 45 controls free of vascular disease under 60 years of age. p22 phox C242T genotypes and MDA levels were determined. Additional information was obtained from each subject on classic risk factors and clinical events of CAD. Genotype distribution in CAD‐patients and controls was thymine–thymine (TT): 13·8% (13·3%), cytosine–thymine (CT): 46·3% (53·3%) and cytosine–cytosine (CC): 39·8% (33·3%), respectively. No significant influence was seen of the p22 phox C242T polymorphism on corresponding mean MDA levels in both groups. Furthermore, age at onset of first time angina pectoris (AP) and myocardial infarction (MCI) was not significantly different between genotype groups. It is concluded that the C242T polymorphism of the p22 phox gene is not associated with lipid peroxidation as measured by MDA, and is not a genetic risk marker for CAD Caucasians.
Immunocytochemical staining of ovarian cyst aspirates with monoclonal antibody against inhibin
Authors: McCLUGGAGE W. G. , PATTERSON A. , WHITE J. , ANDERSON N. H.
Published: March 2003

mccluggage w. g., patterson a., white j. and anderson n. h. (1998) Cytopathology9, 336–342

Immunocytochemical staining of ovarian cyst aspirates with monoclonal antibody against inhibin

Inhibin is a peptide hormone which is produced by ovarian granulosa cells during normal follicular development. It is important that granulosa cells are recognized in fine needle aspirates (FNAs) of ovarian cystic lesions, as this allows definite recognition of a functional cyst and exclusion of a potentially neoplastic epithelial lined cyst. Occasionally the distinction between granulosa and epithelial cells may be difficult, especially when aspirates from functional cysts are unusually cellular. In the present study, FNAs from 33 ovarian cystic lesions were immunostained with a monoclonal antibody against inhibin. Nine cases of peritoneal fluid containing malignant cells in patients subsequently confirmed to have ovarian adenocarcinoma were also stained. Where possible the cytological and immunocytochemical findings were correlated with subsequent biopsy. In most cases in which cytology suggested a functional cyst there was a strong positive staining with anti‐inhibin, although occasional cases were negative. One case originally thought to contain epithelial cells stained strongly positive with anti‐inhibin and on review was felt to represent a cellular functional cyst. In all other cases where cells were considered to be epithelial there was no staining with anti‐inhibin. The study shows that immunocytochemical staining with anti‐inhibin may be of value in confirming the presence of granulosa cells, thus establishing a diagnosis of functional cyst. Although negative staining does not exclude a functional cyst, positive staining with anti‐inhibin allows exclusion of an epithelial lined cyst and may avoid unnecessary surgical intervention.
Cytologic diagnosis and subtyping of rhabdomyosarcoma
Authors: ATAHAN  , AKSU Ö. , EKINCI
Published: March 2003

atahan s,., aksu ö. and ekinci c. (1998) Cytopathology9, 389–397

Cytologic diagnosis and subtyping of rhabdomyosarcoma

We reviewed the cytological findings of 38 cases of rhabdomyosarcoma (RMS) with histological confirmation performed during a period of 15 years and proposed a morphological subtyping based on the most prominent cytologic features. Seventeen of these cases were alveolar, 14 cases embryonal, and seven botryoid subtypes. From these cases, a total of 43 samples, of which 37 were fine needle aspiration (FNA) biopsies and six were touch imprints, were evaluated. Detailed cellular features were identified which enabled differentiation into histological subtypes. In the alveolar RMSs, most tumour cells were small and lymphocyte‐like, having finely granular chromatin. The finding of cells with more abundant cytoplasm, eccentrically located nuclei and bi/multinucleated tumour cells in a background of mucosubstance helped in the differential diagnosis. Two cell types, including large, tadpole or ribbon‐shaped tumour cells and small, round cells with scant cytoplasm, were seen in embryonal RMSs. In botryoid RMSs, a cell type with tightly grouped nuclei within elongated cytoplasm similar to a myotubular structure was observed in addition to the two cell types of embryonal RMSs. We conclude that with experience it will be possible to subtype these tumours by cytologic examination alone.
Inadequate cervical cytology—the need to audit individual smear takers' inadequate rates
Authors: Wilson J. D. , French R. , Branch T. , Sutton J.
Published: March 2003

Inadequate cervical cytology—the need to audit individual smear takers' inadequate rates

In order to assess the performance of individual smear takers, their rates of inadequate smears, due to insufficient material, were monitored between 1992 and 1996. Although the yearly average clinic inadequate rates were all at acceptable levels, there was great variation of rates between smear takers, ranging from 0% to 19.5%. Identification of individuals with unacceptably high inadequate rates allowed them to undergo further training. Continuous monitoring of these inadequate rates can be used to measure levels of performance amongst all smear takers, but is particularly useful for new smear takers, or those who have required retraining.
The role of fine needle aspiration cytology (FNAC) in the investigation of superficial lymphadenopathy; uses and limitations of the technique
Authors: Lioe T. F. , Elliott H. , Allen D. C. , Spence R. A. J.
Published: March 2003

The role of fine needle aspiration cytology (FNAC) in the investigation of superficial lymphadenopathy; uses and limitations of the technique

Aspirates (n = 163) from 157 patients with enlarged superficial lymph nodes were obtained over a 5‐year period in a combined surgical/FNAC clinic. A definitive diagnosis was achieved in over 77% of the cases: benign 52.7%, malignant 25.1%. The diagnostic accuracy was 94.4%, sensitivity 85.4% and specificity 100%. The false‐negative rate was 12.5% but decreased to 3.5% when lymphoma cases were excluded. There were 36 cases of metastatic disease, the majority of which were from a primary breast carcinoma. The main diagnostic difficulty was in distinguishing low‐grade lymphoma from reactive hyperplasia. An added advantage was that aspirated material could be used in ancillary tests to help with the differential diagnosis. FNAC has a well‐defined role in the investigation of superficial lymphadenopathy. Used in the proper setting it will provide a definitive diagnosis in the majority of cases, especially relating to recurrent malignancy or metastatic disease. Patients with a reactive cytological picture and no clinically suspicious symptoms could be spared unnecessary surgery and reviewed through follow up. This technique is cost‐effective, of high diagnostic accuracy, and results in considerable resource savings.
Outcome of women referred to colposcopy for persistently inadequate smears
Authors: Sen C. , Brett M. T.
Published: March 2003

Outcome of women referred to colposcopy for persistently inadequate smears

The outcome of referral to colposcopy of 240 women who had persistently inadequate smears was investigated. Of 232 women who attended colposcopy, 214 (92.2%) had a normal outcome, 12 (5.2%) had low grade abnormalities, and six (2.6%) had high grade abnormalities. This group of women therefore has a negligibly increased risk of harbouring cervical neoplasia. Although not directly comparable, women with a history of previous abnormal cytology did not have a higher risk than those without such a history. Unnecessary colposcopy could have been avoided in the majority of cases if a good quality repeat smear had been taken. Improved smear taker training could decrease the number of referrals. A hospital cytology clinic is proposed as a cost‐effective alternative to colposcopy at the first attendance.
Fine needle aspiration cytology of suspected tuberculous lymphadenitis
Authors: Bezabih M. , Mariam D.W. , Selassie S.G.
Published: March 2003

Fine needle aspiration cytology of suspected tuberculous lymphadenitis

The aims of this cross‐sectional study were to describe the distributional patterns of tuberculous lymphadenitis and to assess the correlation between fine needle aspiration cytology (FNAC) and the Ziehl Neelsen staining technique in diagnosing tuberculous lymphadenitis. Romanowsky's method (Wright's stain) for cytological diagnosis and Ziehl Neelsen (hot method) for the identification of acid‐fast bacilli were utilized. Out of one hundred and twenty‐eight consecutive patients attending the cytological diagnostic service of the Department of Pathology within Jimma University, 89 (69.6%) of the patients were younger than 30 years of age. The male to female ratio was 1.3 : 1. The cervical region was the most common site and involved 95 cases (74.2%), followed by the axillary and inguinal lymph node regions (20.3% and 4.3%, respectively). The Wright's‐stained cytology smears were grouped into three categories: epithelioid granulomas without necrosis, epithelioid granulomas with caseous necrosis and necrosis without epithelioid granulomas. The Ziehl Neelsen stains were undertaken on separate slides: 20.0% of the cases showing epithelioid granulomas without necrosis, 61.9% of those with epithelioid granulomas with necrosis/abscesses and 69.7% of those with necrosis without granulomas were found to be positive for acid‐fast bacilli. The overall positivity for the ZiehlNeelsen stained cases was 59.4%. It can therefore be concluded that FNAC is a reliable diagnostic tool in helping to avert the more invasive surgical procedures undertaken in the diagnosis of tuberculous adenitis. The ZiehlNeelsen stain for identification of acid‐fast bacilli should be incorporated as an adjunct to increase the diagnostic accuracy of tuberculous lymphadenitis.
Cycles in insect populations: delayed density dependence or exogenous driving variables?
Authors: HUNTER MARK D. , PRICE PETER W.
Published: March 2003

SummaryDelayed density dependence, and the cycles in insect populations that it can generate, are often investigated using time‐series analysis. Recently, several authors have raised concerns about the validity of using time‐series analysis to detect density dependence. One particular concern is the suggestion that exogenous driving variables, such as cyclic weather patterns, can lead to the spurious detection of density dependence in natural populations.

Using non‐biological data (the electricity bills of one of the authors), we show how easy it is to be misled by the results of time‐series analysis. We then present 16 years’ data on the gall‐forming sawfly, Euura lasiolepis (Hymenoptera: Tenthredinidae), and show that cycles in weather, specifically winter precipitation, lead to the spurious detection of density dependence in time‐series analysis. We conclude that time‐series analysis cannot stand alone as a method for inferring the action of density dependence, and urge further investigation of the effects of apparent cycles in abiotic forces on insect populations.
Learning pays off: influence of experience on host finding and parasitism in Lariophagus distinguendus
Authors: Steidle Johannes L. M.
Published: March 2003

Abstract.1. The influence of experience on egg maturation, parasitism rate, and behaviour during host searching was investigated for Lariophagus distinguendus (Först.) (Hymenoptera: Pteromalidae) parasitizing larvae of the granary weevil Sitophilus granarius (L.) in grains of wheat Triticum aestivum L.

2. Dissection of female parasitoids and parasitism bioassays at high host density revealed that experience with hosts (e.g. by oviposition or by host feeding) is not required either for triggering oogenesis or for oviposition.

3. In parasitism experiments at low host density, when single host‐infested grains were offered within a bulk of healthy grains, host finding and parasitism rate were increased by experience.

4. Behavioural observations revealed that searching time required for finding an infested grain was shorter for experienced parasitoids than for naive parasitoids, because travel time from grain to grain is shorter for experienced parasitoids, and because experienced parasitoids spend less time than naive parasitoids on non‐infested grains.

5. In conclusion, experience due to host exposure increases parasitism and thereby the fitness of the parasitoids. It is discussed that this increase is more likely due to learning than to different egg load dynamics of experienced parasitoids.
Higher productivity at the cost of increased host‐specificity when Maculinea butterfly larvae exploit ant colonies through trophallaxis rather than by predation
Authors: Thomas J. A. , Elmes G. W.
Published: March 2003

Abstract.1. Field studies were made of the benefits and costs of two feeding strategies in the genus Maculinea, whose final‐instar larvae parasitise Myrmica ant colonies. Maculinea arion is an obligate predator of ant brood, whereas M. rebeli and M. alcon mimic ant larvae and are fed (like cuckoos) directly by the workers.

2. Samples of > 1500 Myrmica nests confirmed laboratory‐based predictions that, by feeding at a lower trophic level, many (4.7‐fold) more individuals of M. rebeli and M. alcon are supported per ant colony than M. arion.

3. Because of their efficient feeding, cuckoo species often occupied sites where their phytophagous early larval populations coincided to only a small extent (> 10%) with host Myrmica colonies, whereas all sites supporting M. arion had 50–100% of the phytophagous stages within foraging range of the host Myrmica species.

4. Greater host‐specificity was identified as another consequence of cuckoo‐feeding. The ecological cost of this is discussed.

5. The feeding of other Maculinea species had not been fully described: the data suggest that M. nausithous is a predator of ant brood and confirm that M. teleius is predacious.
Nutrients, diversity, and community structure of two phytotelm systems in a lower montane forest, Puerto Rico
Authors: Richardson Barbara A. , Rogers Carol , Richardson M. J.
Published: March 2003

1. Bromeliad and heliconia phytotelmata in the same forest area were compared in terms of their animal assemblages, nutrient inputs, and plant architecture.

2. For all major elements, nutrient inputs from canopy‐derived debris and rainfall in bromeliads were significantly lower than those derived from decaying flower parts and plant secretions in heliconia bracts. Bromeliads contained significantly fewer organisms per unit volume of water and unit dry weight of organic matter than did heliconia inflorescences. They also contained a significantly lower animal biomass (199 mg DW from 15 bromeliads, 527 mg DW from 15 heliconia inflorescences).

3. Species richness was independent of abundance, demonstrating that, at least for small container habitats, higher abundance does not necessarily lead to a greater species richness. Communities were remarkably similar in patterns of relative abundance and species richness (23 spp. in bromeliads, 21 spp. in heliconia), probably due to functional similarities in plant architecture, with the two most abundant species comprising 60–62% of the total community. Coefficients of similarity were low because of marked differences in species assemblages.

4. Some taxa were phytotelm generalists but most showed a preference for one particular habitat, indicating differential selection in the choice of oviposition sites and larval development within the forest ecosystem. In common with many island communities, species richness was lower than that reported for these phytotelm habitats in mainland central and south America.
Ecological interactions of Pseudacteon parasitoids and Solenopsis ant hosts: environmental correlates of activity and effects on competitive hierarchies
Authors: Morrison Lloyd W. , Kawazoe Elizabeth A. , Guerra Rodney , Gilbert Lawrence E.
Published: March 2003

1. Solenopsis (Hymenoptera: Formicidae) fire ants are host to Pseudacteon (Diptera: Phoridae) parasitoids. The activity of S. geminata (F.) hosts and relative abundance of Pseudacteon phorids, along with five environmental variables, were measured at weekly intervals over an 8‐month period at two sites.

2. Pseudacteon relative abundances often varied greatly from week to week, and were only weakly positively correlated with S. geminata activity.

3. A quadratic function of soil temperature was the single best predictor of ant activity at both sites, explaining 32 and 73% of the variation in ant activity. A linear function of soil moisture was the single best predictor of phorid relative abundance at one site (r2 = 0.23) whereas no measured variables were significant predictors of phorid relative abundance at the other site.

4. Interspecific interactions at 600 baits were monitored at a third site to document dominance hierarchies and determine whether the presence of Pseudacteon phorids mediated interspecific interactions in their host, S. geminata.

5. Solenopsis geminata was near the top of dominance hierarchies, which did not diverge greatly from a linear pattern. Three species (S. geminata, S. invicta Buren, and Crematogaster laeviuscula Mayr) won the majority of their interspecific interactions and appear to be co‐dominants at this microhabitat‐rich site.

6. Overall, the presence of phorids had no significant effect on the outcome of interspecific contests involving S. geminata and all other ant species grouped together. Phorids may have contributed to some of the S. geminata losses against other co‐dominant species.
Pollinator genetics and pollination: do honey bee colonies selected for pollen‐hoarding field better pollinators of cranberry Vaccinium macrocarpon?
Authors: Cane James H. , Schiffhauer Daniel
Published: March 2003

1. Genetic polymorphisms of flowering plants can influence pollinator foraging but it is not known whether heritable foraging polymorphisms of pollinators influence their pollination efficacies. Honey bees Apis mellifera L. visit cranberry flowers for nectar but rarely for pollen when alternative preferred flowers grow nearby.

2. Cranberry flowers visited once by pollen‐foraging honey bees received four‐fold more stigmatic pollen than flowers visited by mere nectar‐foragers (excluding nectar thieves). Manual greenhouse pollinations with fixed numbers of pollen tetrads (0, 2, 4, 8, 16, 32) achieved maximal fruit set with just eight pollen tetrads. Pollen‐foraging honey bees yielded a calculated 63% more berries than equal numbers of non‐thieving nectar‐foragers, even though both classes of forager made stigmatic contact.

3. Colonies headed by queens of a pollen‐hoarding genotype fielded significantly more pollen‐foraging trips than standard commercial genotypes, as did hives fitted with permanently engaged pollen traps or colonies containing more larvae. Pollen‐hoarding colonies together brought back twice as many cranberry pollen loads as control colonies, which was marginally significant despite marked daily variation in the proportion of collected pollen that was cranberry.

4. Caloric supplementation of matched, paired colonies failed to enhance pollen foraging despite the meagre nectar yields of individual cranberry flowers.

5. Heritable behavioural polymorphisms of the honey bee, such as pollen‐hoarding, can enhance fruit and seed set by a floral host (e.g. cranberry), but only if more preferred pollen hosts are absent or rare. Otherwise, honey bees' broad polylecty, flight range, and daily idiosyncrasies in floral fidelity will obscure specific pollen‐foraging differences at a given floral host, even among paired colonies in a seemingly uniform agricultural setting.
Bimodal life cycle of the burying beetle Nicrophorus quadripunctatus in relation to its summer reproductive diapause
Authors: Nisimura Tomoyosi , Kon Masahiro , Numata Hideharu
Published: March 2003

Abstract 1. Under natural conditions in Kyoto, Japan, the reproductive activities of Nicrophorus quadripunctatus Kraatz (Coleoptera: Silphidae) decreased in summer and the species showed a bimodal life cycle.

2. In the laboratory, most adult pairs raised at 20 °C under a LD 12:12 h regime reproduced when provided with a piece of chicken. In adults raised at 20 °C under a LD 16:8 h regime, however, both reproductive behaviour and ovarian development were reduced. It is concluded that these adults entered a reproductive summer diapause.

3. High temperature (25 °C) also suppressed the reproductive behaviour even under a favourable LD 12:12 h regime. In the field, therefore, adults reduce their reproductive activity in summer because of diapause induced by long‐day photoperiods and direct inhibition of reproduction by high temperatures.

4. When the temperature was changed from 20 °C to 25 °C immediately after hatching of larvae, they reached the wandering stage in 95% of adult pairs. When the temperature was changed from 20 °C to 25 °C immediately after oviposition, however, no larvae hatched in 85% of pairs. Egg mortality was significantly higher at 25 °C than at 20 and 22.5 °C; no eggs hatched at 27.5 °C. The physiological mechanisms for reducing reproduction probably prevent the beetles from inefficient oviposition in summer.
Priority effects of bamboo‐stump mosquito larvae: influences of water exchange and leaf litter input
Authors: Sunahara Toshihiko , Mogi Motoyoshi
Published: March 2003

Abstract 1. A series of laboratory experiments was conducted to examine the influences of leaf litter input and flushing of medium on the priority effects of the two bamboo‐stump breeding mosquitoes, Aedes albopictus and Tripteroides bambusa, using 150‐ml microcosms. Larvae of either species were introduced to microcosms on day 0 (early cohort), at different densities, and day 14 (late cohort). The effects of the early cohort on survival, pupation, and biomass yield of the late cohort were compared among various combinations of the two species and among different treatments (water exchange, leaf addition, both of them, neither of them) on days 14 and 44.

2. Survivorship and pupation success of the late A. albopictus cohort were affected negatively by the presence of either species of the early cohort to a greater extent than those of the late T. bambusa cohort.

3. Water exchange reduced mortality of the late A. albopictus cohort over a short term in the presence of the early cohort of either species, indicating that a toxic substance was involved in the inhibitory priority effects. The addition of leaf litter enhanced survivorship and pupation of the late A. albopictus cohort, whether or not water was exchanged. The late T. bambusa cohort showed high survival rate with all treatments.

4. The results indicate that leaf‐litter input moderates the inhibitory priority effects on A. albopictus larvae, not only by supplying food resources but also by alleviating the toxicity of accumulated dissolved substances.
A comparison of the host‐searching efficiency of two larval parasitoids of Plutella xylostella
Authors: Wang Xin‐Geng , Keller Michael A.
Published: March 2003

1. A host specialist parasitoid is thought to have greater efficiency in locating hosts or greater ability to overcome host defence than a generalist species. This leads to the prediction that a specialist should locate and parasitise more hosts than a generalist in a given arena. The work reported here tested these predictions by comparing the host‐searching behaviour of Diadegma semiclausum (a specialist) and Cotesia plutellae (an oligophagous species), two parasitoids of larval Plutella xylostella.

2. Both parasitoids employed antennal search and ovipositor search when seeking hosts but D. semiclausum also seemed to use visual perception in the immediate vicinity of hosts.

3. Larvae of P. xylostella avoided detection by parasitoids by moving away from damaged plant parts after short feeding bouts. When they encountered parasitoids, the larvae wriggled vigorously as they retreated and often hung from silk threads after dropping from a plant.

4. These two parasitoids differed in their responses to host defences. Diadegma semiclausum displayed a wide‐area search around feeding damage and waited near the silk thread for a suspended host to climb up to the leaf, then attacked it again. Cotesia plutellae displayed an area‐restricted search and usually pursued the host down the silk thread onto the ground.

5. Diadegma semiclausum showed a relatively fixed behavioural pattern leading to oviposition but C. plutellae exhibited a more plastic behavioural pattern.

6. The time spent by the two parasitoids on different plants increased with increasing host density, but the time spent either on all plants or a single plant by D. semiclausum was longer than that of C. plutellae. Diadegma semiclausum visited individual plants more frequently than C. plutellae before it left the patch, and stung hosts at more than twice the rate of C. plutellae.

7. The results indicated that the host‐location strategies employed by D. semiclausum were adapted better to the host's defensive behaviour, and thus it was more effective at detecting and parasitising the host than was C. plutellae.
Glucose intolerance in familial combined hyperlipidaemia
Authors: Vakkilainen  , Porkka  , Nuotio  , Pajukanta  , Suurinkeroinen  , Ylitalo  , Viikari  , Ehnholm  , Taskinen  ,   for the EUFAM study group
Published: March 2003

Background

Familial combined hyperlipidaemia (FCHL) is a common hereditary disorder. Hypertriglyceridaemia is associated with glucose intolerance and insulin resistance.

Methods

To study glucose tolerance in FCHL patients with different lipid phenotypes [hypercholesterolaemia (IIA), mixed hyperlipidaemia (IIB), hypertriglyceridaemia (IV)], we investigated 253 family members and 92 spouses arising from 33 well‐defined Finnish FCHL pedigrees.

Results

In oral glucose tolerance tests. the affected family members had higher values for glucose area under the curve than did non‐affected family members (673 ± 127 min mmol L−1, 754 ± 145 min mmol L−1, 846 ± 180 min mmol L−1 and 838 ± 183 min mmol L−1 for phenotypes normal, IIA, IIB and IV respectively; P < 0.001 after adjustment for body mass index, waist circumference and age). Impaired glucose tolerance and diabetes were more common among affected than non‐affected family members (prevalences of normal glucose tolerance 94.0%, 80.0%, 54.3% and 58.5% for phenotypes normal, IIA, IIB and IV).

Conclusion

Affected FCHL family members were more glucose intolerant than non‐affected family members. In men, this disturbance was not related to lipid phenotype nor was it explained by obesity.
Bezafibrate down‐regulates fibrinogen biosynthesis in human hepatoma HepG2 cells
Authors: Binsack  , Stegmeier  , Dörge  , Völkl
Published: March 2003

Background

Bezafibrate reportedly lowers serum lipids and plasma fibrinogen in humans and rats, but the mechanism of this process has still to be clarified. We have addressed this problem by investigating the effects of bezafibrate on fibrinogen in the human hepatoma HepG2 cell line.

Methods

In cells cultured with and without bezafibrate, intra‐ and extracellular fibrinogen was quantified using an enzyme‐linked immunosorbent assay (ELISA), and changes in the biosynthesis and secretion of bezafibrate were monitored by [35S]‐methionine labelling. In addition, expression of the corresponding mRNA was investigated by Northern blotting. As fibrinogen is an acute‐phase protein, HepG2 cells exposed to interleukin 6 were also analysed.

Results

Bezafibrate decreased fibrinogen biosynthesis by about 25%, regardless of whether or not the cultures were also exposed to interleukin 6. mRNA was reduced in proportion to the concentration of interleukin 6 to which the cells were exposed, but intracellular transport and release of the protein were not affected.

Conclusion

Apparently, bezafibrate interferes with the biosynthesis of fibrinogen at the pretranslational level but does not affect the export of the protein.
Antioxidants inhibit the in vitro production of inflammatory cytokines in Crohn's disease and ulcerative colitis
Authors: Reimund  , Allison  , Muller  , Dumont  , Kenney  , Baumann  , Duclos  , Poindron
Published: March 2003

Background

Modulation of cytokine secretion may be of interest in the treatment of Crohn's disease or ulcerative colitis.

Methods

The effect of three antioxidants — butylated hydroxyanisol, tetrahydropapaveroline and nordihydroguaiaretic acid — on the production of tumour necrosis factor (TNF), interleukin (IL) 1, IL‐6 and IL‐8 (measured by enzyme‐linked immunosorbent assay) by peripheral mononuclear cells and biopsies of inflamed colonic mucosa from inflammatory bowel disease patients were studied.

Results

We observed a decrease in IL‐1 and IL‐6 production by peripheral mononuclear cells from inflammatory bowel disease patients (approximately 50% of control). The three drugs did not decrease IL‐6 and IL‐8 secretion by colonic biopsies, whereas they did inhibit IL‐1 and, to some degree, TNF production. The cytokine‐inhibitory effect of antioxidants seems to be more pronounced in ulcerative colitis than in Crohn's disease.

Conclusion

Our results suggest that the studied antioxidants, or related compounds, may be of interest in inflammatory bowel disease treatment.
Relationship between blood pressure, metabolic variables and blood flow in obese subjects with or without non‐insulin‐dependent diabetes mellitus
Authors: Jansson  , Larsson  , Lönnroth
Published: March 2003

Background

To assess the relationship between systemic blood pressure, metabolic variables and adipose tissue blood flow, we studied 55 subjects before and 36 subjects after an oral glucose load (100 g).

Methods

The subjects were divided into four different groups: (a) young lean control subjects [age 31 ± 1 years, mean ± SE, BMI (body mass index) 22.7 ± 0.4 kg m−2]; (b) young obese subjects (age 29 ± 2 years, BMI 37.8 ± 1.8 kg m−2); (c) middle‐aged obese subjects (age 50 ± 2 years, BMI 30.2 ± 0.9 kg m−2); and (d) middle‐aged obese non‐insulin‐dependent diabetic (NIDDM) subjects (age 54 ± 2 years, BMI 30.0 ± 0.7 kg m−2).

Results

Groups 2–4 demonstrated a low fasting adipose tissue blood flow (ATBF) and the increase in ATBF after oral glucose was impaired. A further impairment was present in NIDDM subjects. Systolic and diastolic blood pressure were also increased in groups 2–4 and further so in group 4. Fasting glucose, lactate and free fatty acid (FFA) levels correlated positively with the systolic blood pressure, whereas ATBF correlated negatively with the diastolic blood pressure. Furthermore, in the NIDDM subjects fasting lactate correlated closely with both the systolic (r = 0.649, P = 0.01) and diastolic (r = 0.626, P = 0.013) blood pressure.

Conclusion

These data suggest a close relationship between insulin resistance and regulation of adipose tissue blood flow as well as blood pressure.
High‐energy phosphates metabolism and recovery in reperfused ischaemic hearts
Authors: Samaja  , Allibardi  , De Jonge  , Chierchia
Published: March 2003

Background

The aim of this study was to assess how coronary flow, oxygen supply and energy demand affect myocardial ATP, phosphocreatine and their metabolites during oxygen shortage and recovery.

Methods

Isolated rat hearts were exposed for 20 min to either low‐flow ischaemia or hypoxaemia at the same oxygen supply, followed by return to baseline conditions (20 min). Seventy‐three hearts were divided into four groups: ischaemic or hypoxaemic, spontaneously beating or paced to increase energy demand.

Results

During O2 shortage, myocardial performance was less in ischaemic, spontaneously beating hearts (SpIs), than in the other groups (14 ± 1% of baseline vs. 25–48%). Consequently, the tissue levels of ATP, total adenylates and phosphocreatine were maintained in SpIs, in contrast to marked decreases in the other groups. Upon reflow, the recovery of performance and of myocardial ATP was 94 ± 5% in SpIs (P = NS vs. baseline) compared with 64–85% (P < 0.05 vs. baseline) in the other groups. The degree of recovery was positively related to the ischaemic contents of ATP (P = 0.03) and adenylates (P = 0.001), but not to that of phosphocreatine (P = NS).

Conclusion

The maintenance of the ATP pool under low oxygen supply conditions is essential for good recovery. The most important factors that determine the ATP pool size are the energy demand, which increases the formation of diffusible ATP catabolites, and the coronary flow, which removes these catabolites, rather than the oxygen supply per se.
Peripheral markers of oxidative stress in probable Alzheimer patients
Authors: Repetto  , Reides  , Evelson  , Kohan  , De Lustig  , Llesuy
Published: March 2003

Background

The current research on Alzheimer's disease is mainly focused in the post‐mortem characterization of pathological and biochemical alterations in the brain. The finding of peripheral markers that could be associated with the changes observed in the Alzheimer's brain would be of interest in this field. The aim of the present study was to evaluate the state of different peripheral markers of oxidative stress in probable Alzheimer patients and compare them with a group of healthy individuals.

Design

The determinations made include the plasma total antioxidant capacity (TRAP) and tert‐butyl hydroperoxide‐initiated chemiluminescence and catalase activity in erythrocytes from 18 patients with probable Alzheimer's disease and 18 matched control subjects with normal cognitive function.

Results

TRAP was decreased in Alzheimer patients by 24% (control group 308 μmol L−1 Trolox, SEM 34, n = 18). tert‐Butyl hydroperoxide‐initiated chemiluminescence and catalase activity showed an increase in erythrocytes from Alzheimer patients by 52% (control group 116 700 cps mg−1 haemoglobin, SEM 6690) and 75% (control group 2.55 pmol mg−1 protein, SEM 0.39, n = 18) respectively.

Conclusion

Oxidative stress in the blood of probable Alzheimer patients could be a reflection of the brain condition and suggests that oxygen free radicals could be partially responsible of the damage observed in this disease.
Serum hyaluronan as a predictor of hepatic regeneration after hepatectomy in humans
Authors: Ogata  , Okuda  , Ueno  , Saito  , Aoyagi
Published: March 2003

Background

The capacity for hepatic regeneration after hepatectomy is important for allowing surgeons to determine the appropriate extent of resection. However, conventional preoperative liver function tests are unsatisfactory for estimating the post‐operative regenerative capacity of the remnant liver. The aim of this study was to evaluate the relationship between preoperative serum hyaluronan and hepatic regeneration.

Methods

Preoperative serum hyaluronan levels and the hepatic regeneration rate were estimated in 49 patients using computerized tomographic volumetry. The hepatic fibrotic rate was calculated with non‐tumorous tissues stained with Azan–Mallory. Immunolocalization of factor VIII‐related antigen (FVIIIAg) was examined as a marker for hepatic sinusoidal capillarization.

Results

The serum hyaluronan level was significantly correlated with the hepatic regeneration rate (P < 0.001). Patients with serum hyaluronan levels below 200 ng mL−1 exhibited a significant correlation between the hepatic regeneration rate and the hepatic fibrotic rate. However, patients with serum hyaluronan levels above 200 ng mL−1 did not demonstrate a distinct correlation. The hepatic regeneration rate of patients with FVIIIAg in the liver and serum hyaluronan levels above 200 ng mL−1 were very low compared with those without FVIIIAg (P < 0.001). Multiple regression analysis revealed that serum hyaluronan was a significant predictor of post‐operative hepatic regeneration among several clinical variables (r = 0.857, R2 = 0.735).

Conclusion

It has been suggested that hepatic regeneration is closely related to both hepatic fibrosis and hepatic sinusoidal capillarization. The serum hyaluronan level is regarded as a useful predictor for hepatic regeneration after hepatectomy.
Mitochondrial myopathies and encephalomyopathies
Authors: Schapira  , Cock
Published: March 2003

Defects of mitochondrial metabolism result in a wide variety of human disorders, which can present at any time from infancy to late adulthood and involve virtually any tissue either alone or in combination. Abnormalities of the electron transport and oxidative phosphorylation (OXPHOS) system are probably the most common cause of mitochondrial diseases. Thirteen of the protein subunits of OXPHOS are encoded by mitochondrial DNA (mtDNA) and mutations of this genome are important causes of OXPHOS deficiency. The link between genotype and phenotype with respect to mtDNA mutations is not clear: the same mutation may result in a variety of phenotypes, and the same phenotype may be seen with a variety of different mtDNA mutations. The pathogenesis of mtDNA mutations is unclear although OXPHOS and ATP deficiency, and free radical generation, are thought to contribute to tissue dysfunction. There is now strong evidence for mitochondrial dysfunction in neurodegenerative disorders. In some cases, e.g. Friedreich's ataxia, hereditary spastic paraplegia, this is a result of a mutation of a nuclear gene encoding a mitochondrial protein, whilst in others, e.g. Huntington's disease, amyotrophic lateral sclerosis, the OXPHOS defect is secondary to events induced by a mutation in a nuclear gene encoding a non‐mitochondrial protein. In yet a third group, e.g. Parkinson's disease, Alzheimer's disease, the relationship of the mitochondrial defect to aetiology and pathogenesis is unclear.
Platelet–collagen interactions: membrane receptors and intracellular signalling pathways
Authors: Alberio  , Dale
Published: March 2003

Platelet adhesion to and activation by exposed subendothelial collagen plays a critical role in normal haemostasis and pathological thrombosis. Recent advances in elucidating the mechanisms underlying platelet–collagen interaction support a ‘two‐site, two‐step’ model. Direct platelet binding to integrin α2β1 mainly sustains adhesion and allows recognition of glycoprotein VI. The latter interaction is responsible for characteristic intracellular signalling events leading to p72Syk and PLCγ2 activation. The present review describes the known collagen receptors on platelets and discusses the current understanding of signal transduction promoted by collagen.