bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variations in motor unit recruitment patterns occur within and between muscles in the running rat (Rattus norvegicus)
Authors: Hodson-Tole E. F. , Wakeling J. M. 
Published: June 2007

SUMMARYMotor units are generally considered to follow a set, orderly pattern of recruitment within each muscle with activation occurring in the slowest through to the fastest units. A growing body of evidence, however, suggests that recruitment patterns may not always follow such an orderly sequence. Here we investigate whether motor unit recruitment patterns vary within and between the ankle extensor muscles of the rat running at 40 cm s-1 on a level treadmill. In the past it has been difficult to quantify motor unit recruitment patterns during locomotion; however, recent application of wavelet analysis techniques has made such detailed analysis of motor unit recruitment possible. Here we present methods for quantifying the interplay of fast and slow motor unit recruitment based on their myoelectric signals. Myoelectric data were collected from soleus, plantaris and medial gastrocnemius muscles representing populations of slow, mixed and fast fibres, respectively, and providing a good opportunity to relate myoelectric frequency content to motor unit recruitment patterns. Following wavelet transformation, principal component analysis quantified signal intensity and relative frequency content. Significant differences in signal frequency content occurred between different time points within a stride (P&lt;0.001). We optimised high- and low-frequency wavelets to the major signals from the fast and slow motor units. The goodness-of-fit of the optimised wavelets to the signal intensity was high for all three muscles (r2&gt;0.98). The low-frequency band had a significantly better fit to signals from the soleus muscle (P&lt;0.001), while the high-frequency band had a significantly better fit to the medial gastrocnemius(P&lt;0.001).
Identification and cardiotropic actions of sulfakinin peptides in the American lobster Homarus americanus
Authors: Dickinson Patsy S. , Stevens Jake S. , Rus Szymon , Brennan Henry R. , Goiney Christopher C. , Smith Christine M. , Li Lingjun , Towle David W. , Christie Andrew E. 
Published: June 2007

SUMMARY
In arthropods, a group of peptides possessing a–Y(SO3H)GHM/LRFamide carboxy-terminal motif have been collectively termed the sulfakinins. Sulfakinin isoforms have been identified from numerous insect species. In contrast, members of this peptide family have thus far been isolated from just two crustaceans, the penaeid shrimp Penaeus monodon and Litopenaeus vannamei. Here, we report the identification of a cDNA encoding prepro-sulfakinin from the American lobster Homarus americanus. Two sulfakinin-like sequences were identified within the open-reading frame of the cDNA. Based on modifications predicted by peptide modeling programs, and on homology to the known isoforms of sulfakinin, particularly those from shrimp, the mature H. americanus sulfakinins were hypothesized to be pEFDEY(SO3H)GHMRFamide (Hoa-SK I) and GGGEY(SO3H)DDY(SO3H)GHLRFamide (Hoa-SK II). Hoa-SK I is identical to one of the previously identified shrimp sulfakinins, while Hoa-SK II is a novel isoform. Exogenous application of either synthetic Hoa-SK I or Hoa-SK II to the isolated lobster heart increased both the frequency and amplitude of spontaneous heart contractions. In preparations in which spontaneous contractions were irregular, both peptides increased the regularity of the heartbeat. Our study provides the first molecular characterization of a sulfakinin-encoding cDNA from a crustacean, as well as the first demonstration of bioactivity for native sulfakinins in this group of arthropods.
Salinity-stimulated changes in expression and activity of two carbonic anhydrase isoforms in the blue crabCallinectes sapidus
Authors: Serrano Laetitia , Halanych Kenneth M. , Henry Raymond P. 
Published: June 2007

SUMMARYTwo isoforms of the enzyme carbonic anhydrase (CA) in the blue crab gill,CasCAg and CasCAc, were identified, sequenced, and found to match the membrane-associated and cytoplasmic isoforms, respectively. The membrane-associated isoform is present in much higher levels of mRNA expression in both anterior and posterior gills in crabs acclimated to high salinity (35 p.p.t.), but expression of the cytoplasmic isoform in the posterior gill undergoes a significantly greater degree of up-regulation after exposure to low salinity (15 p.p.t.). CasCAc has the largest scope of induction (100-fold) reported for any transport-related protein in the gill,and this may be necessary to overcome diffusion limitations between gill cytoplasm and the apical boundary layer. Furthermore, the timing of the changes in expression of CasCAc corresponds to the timing of the induction of protein-specific CA activity and CA protein concentration. No changes in CA mRNA expression or activity occur in the anterior gills. The pattern of up-regulation of expression of mRNA of the α-subunit of the Na+/K+-ATPase is similar to that for CasCAc, and both precede the establishment of the new acclimated physiological state of the crab in low salinity. A putative `housekeeping' gene, arginine kinase, also showed about a threefold increase in expression in response to low salinity,but only in the posterior gills. These results suggest that for studies of expression in crustacean gill tissue, a control tissue, such as the anterior gill, be used until an adequate control gene is identified.
Extreme anoxia tolerance in embryos of the annual killifishAustrofundulus limnaeus: insights from a metabolomics analysis
Authors: Podrabsky Jason E. , Lopez James P. , Fan Teresa W. M. , Higashi Richard , Somero George N. 
Published: June 2007

SUMMARYThe annual killifish Austrofundulus limnaeus survives in ephemeral pond habitats by producing drought-tolerant diapausing embryos. These embryos probably experience oxygen deprivation as part of their normal developmental environment. We assessed the anoxia tolerance of A. limnaeus embryos across the duration of embryonic development. Embryos develop a substantial tolerance to anoxia during early development, which peaks during diapause II. This extreme tolerance of anoxia is retained during the first 4 days of post-diapause II development and is then lost. Metabolism during anoxia appears to be supported mainly by production of lactate, with alanine and succinate production contributing to a lesser degree. Anoxic embryos also accumulate large quantities of γ-aminobutyrate (GABA), a potential protector of neural function. It appears that the suite of characters associated with normal development and entry into diapause II in this species prepares the embryos for long-term survival in anoxia even while the embryos are exposed to aerobic conditions. This is the first report of such extreme anoxia tolerance in a vertebrate embryo, and introduces a new model for the study of anoxia tolerance in vertebrates.
Effect of aerial O2 partial pressure on bimodal gas exchange and air-breathing behaviour inTrichogaster leeri
Authors: Alton Lesley A. , White Craig R. , Seymour Roger S. 
Published: June 2007

SUMMARYThe effects of experimental alterations of aerial O2 partial pressure (PO2,air) on bimodal gas exchange and air-breathing behaviour were investigated in the aquatic air-breathing fish Trichogaster leeri in normoxic water. Fish responded to increasing PO2,air by decreasing air-breathing frequency,increasing aerial O2 consumption rate(V̇O2), increasing mean O2 uptake per breath(V̇O2/breath) and decreasing aquatic V̇O2 to maintain a constant total V̇O2. The rate of oxygen uptake from the air-breathing organ (ABO) during apnoea(V̇O2,ap) was derived on a breath-by-breath basis from VO2/breath and apnoea duration. V̇O2,ap and estimates of ABO volume were used to calculate the PO2 in the ABO at the end of apnoea. This increased with increasing PO2,air, suggesting that ABO-PO2 is not regulated at a constant level by internal chemoreceptors. Furthermore, mean V̇O2,ap increased with increasing PO2,air, indicating that the observed increase in V̇O2/breath with increasing PO2,air was facilitated not only by an increase in apnoea duration but also by an increase in the air–blood PO2 gradient.
Establishing combustion temperature in a hydrogen-fuelled engine using spectroscopic measurements
Authors: Ciatti S A , Bihari B , Wallner T 
Published: June 2007

The results reported in this article are based upon spectrographic measurements taken form a single-cylinder hydrogen-powered internal combustion engine. The goals, as stated by the US Department of Energy, are for hydrogen engines to achieve 45 per cent peak brake thermal efficiency, 0.07 g/mile NO x emissions, and US $45/kW. One of the primary research interests in hydrogen engines is to ensure operation of the engine without requiring NO x after-treatment. A reliable method to measure combustion temperature will be useful to achieve this goal. However, unlike most hydrocarbon combustion systems that emit soot radiation, hydrogen combustion provides little in the way of measurable radiation emission except for the excited state of the hydroxyl radical (OH∗). An optical fibre was inserted into the cylinder head of this engine to capture the photons emitted by the OH∗ radical during combustion. Based upon the distribution of the intensity of photons emitted in the 306–310 nm band, the temperature of the OH∗ radical can be calculated. A computer algorithm was used to simulate the energy distribution. This simulated distribution is then compared with the measured distribution, iterating the simulation by change of temperature until it appropriately matches the measured distribution. This diagnostic also has potential application to combustion systems that also do not emit soot radiation; advanced low-temperature combustion concepts such as homogeneous charge compression ignition.
Prevalence of increased serum creatine kinase activity due to macro-creatine kinase and experience of screening programmes in district general hospitals
Authors: Fahie-Wilson Michael N , Burrows Sally , Lawson Graham J , Gordon Tania , Wong Way , Dasgupta Bhaskar 
Published: June 2007

Background: Macro creatine kinase type 1 (MCK1) may be the cause of elevated total serum CK activity, which can lead to diagnostic confusion. There is evidence that this problem is poorly recognized perhaps due to a lack of information on its prevalence. Precipitation with polyethylene glycol (PEG) has been described for the detection of MCK1 but has not been fully evaluated. Methods: We introduced a screening programme to detect elevated serum total CK due to MCK1 and determine the prevalence of this problem using PEG precipitation with confirmation by gel filtration chromatography (GFC). The results were compared with those from a laboratory which selected samples for further investigation during the clinical validation process. We also studied characteristics of the PEG precipitation test including sensitivity and specificity when compared with GFC. Results: Over 2 years we screened 368 patients. In 17 cases the proportion of CK activity precipitated by PEG was relatively high and the presence of MCK1 was confirmed in seven by GFC. In a second laboratory, over a period of 5 years, 11 samples were selected during the clinical validation process for further study and MCK1 was the cause of the elevated CK activity in six cases. PEG precipitates a proportion of normal, uncomplexed CK and this is increased by increasing serum globulin concentration and by higher concentrations of PEG. Conclusions: The prevalence of elevated serum CK activity due to MCK1 was approximately 2%. Laboratories should consider introducing a systematic screening programme based on PEG precipitation.
Stability of creatinine with delayed separation of whole blood and implications for eGFR
Authors: Shepherd J , Warner M H , Kilpatrick E S 
Published: June 2007

Background: The stability of creatinine in whole blood is unclear: it is not known if analysis of creatinine in samples with delayed separation could lead to misclassification of chronic kidney disease (CKD) using estimated glomerular filtration rate (eGFR). Methods: Multiple blood samples were taken at a single time-point from five individuals and subject to varying time delays prior to centrifugation, after which serum was separated and analysed for creatinine by five different methods. The effect of time delay on eGFR was further investigated by measuring creatinine on duplicate patient samples arriving in the laboratory after immediate and delayed centrifugation. Results: A significant increase in creatinine was seen by 24 h using kinetic Jaffe methods ( P<0.025). Over a period of 31 h creatinine concentration was stable using enzymatic creatinine assays. Using duplicate patient samples, four of 21 patients where specimens were delayed in the laboratory by more than 10 h showed a misclassification of CKD. Conclusion: Delays in sample receipt can lead to significant increases in measured creatinine and misclassification of CKD. Enzymatic creatinine assays are reliable with respect to delayed sample receipt over the time course studied.
Extended storage of whole blood with 3-deazaadenosine for homocysteine assay
Authors: Hansrani Monica , Stansby Gerard 
Published: June 2007

Background: To assess the effectiveness of using 3-deazaadenosine (3DAA) to maintain plasma homocysteine concentrations (tHCy) in whole blood samples. Methods: Blood was obtained from five volunteers and samples were maintained at room temperature, in cold packs or in a fridge (0-4°C) with and without 3DAA. At time points ranging from 6 to 168 h, samples were processed and analysed for tHCy using the Abbott IMx system. Results: There was a mean increase in tHCy of 29.4% at 6 h increasing to 242.6% after 168 h in whole blood kept at room temperature. There was no significant change in tHCy for 48 h when stored in cold packs, and for 72 h when stored in the fridge. The addition of 3DAA had a significant preservative effect ( P<0.001), maintaining tHCy to 48 h in whole blood at room temperature, 120 h in the fridge and 96 h in cool packs. There was no statistical difference in results obtained from samples containing preservative and controls when using the Abbott IMx system. Conclusion: 3DAA is an effective preservative of tHCy in whole blood, particularly in samples maintained at 0-4°C.
Cardiac troponin I concentrations in people presenting with diabetic ketoacidosis
Authors: Geddes J , Deans K A , Cormack A , Motherwell D , Paterson K , O'Reilly D St J , Fisher B M 
Published: June 2007

Background: Elevated troponin concentrations may be observed in a wide spectrum of medical disorders in people without evidence of overt ischaemic heart disease. The prospective relationship between serum cardiac troponin I (cTnI) and diabetic ketoacidosis (DKA) has not been examined in adults. Methods: Forty patients (14 male and 26 female) with type 1 diabetes were recruited. cTnI, creatine kinase (CK), cystatin C and beta-hydroxybutyrate were measured on admission and at 24, 48 and 72 h post-admission. Daily electrocardiographs were also performed. Results: Four out of forty subjects presenting with DKA had an increase in cTnI (median (SD) 0.06 (0.31) μg/L). One of the subjects had multiple possible reasons for the elevated cTnI concentration. However, the other three subjects had no obvious precipitating factors. This cohort underwent echocardiography and thallium-201 scintigraphy, which revealed no abnormalities. Conclusions: Minor troponin elevations appear to occur in a small number of subjects with type 1 diabetes presenting with DKA. The clinical relevance of this at this stage remains unknown and further large-scale studies are suggested.
Serum remnant lipoprotein cholesterol/triglyceride ratio as an index for screening familial type III hyperlipidaemia
Authors: Nakajima Katsuyuki , Daimon Masahiro , Kamiyama Kiyoshi , Takanashi Kunihiko , Suzuki Yukiko , Watanabe Masakazu , Kubono Katsuo , Saniabadi Abby R , Takashima Sei-Ichi , Sakurabayashi Ikunosuke 
Published: June 2007

Background: An elevated serum remnant lipoprotein cholesterol (RLP-C)/triglyceride (TG) ratio has not been evaluated as an index of familial type III hyperlipidaemia defined by the presence of β-VLDL and apolipoprotein (Apo) E2/2 phenotype in the Japanese hyperlipidaemic population. Methods: Serum lipids and lipoproteins from 514 individuals (200 men and 314 women, mean age 58 years) with total cholesterol >6.22 mmol/L and TG between 2.26 mmol/L and 9.04 mmol/L, selected from 25,080 subjects visiting the clinics for health checkup were analysed for a possible relationship with familial type III hyperlipoproteinaemia. Results: Median RLP-C concentration and RLP-C/TG ratio were 0.30 and 0.11 mmol/L, respectively. When compared between subjects with (31 cases) and without (483 cases) a broad-beta band on electrophoresis, the RLP-C concentrations and RLP-C/TG ratio were 0.77±0.43 mmol/L versus 0.34±0.16 mmol/L ( P<0.0001) and 0.15±0.023 versus 0.11±0.027 ( P<0.0001), respectively. Three cases with broad-beta band positive (the presence of β-VLDL) showed RLP-C/TG ratio greater than 0.23 and RLP-C greater than 0.78 mmol/L, suggestive of type III hyperlipoproteinaemia, despite a lack of characteristic Apo E2/2 homozygosity. Cases with Apo E/Apo CIII ratio greater than 1.0 were not detected in this study group. Conclusion: Serum RLP-C concentration and RLP-C/TG ratio, together with Apo E/Apo CIII ratio appear to be useful for screening familial type III hyperlipidaemia in the Japanese hyperlipidaemic population.
Validity of simplified protocols to estimate glomerular filtration rate using iohexol clearance
Authors: James T J , Lewis A V , Tan G D , Altmann P , Taylor R P , Levy J C 
Published: June 2007

Background: Iohexol clearance is an accurate and precise exogenous marker of glomerular filtration rate (GFR), but protocols are generally lengthy or require multiple sampling. Shorter or simpler protocols would be more practicable. Methods: Two clearance estimates, two weeks apart, were undertaken in 11 healthy individuals and 26 diabetic patients with minimal to moderate renal impairment (chronic kidney disease stages 1-3). Blood specimens withdrawn at 60, 90, 120, 150, 180 and 240 min post-iohexol were analysed for iohexol. Results: Visit 1 demonstrated excellent correlation with visit 2 (slope 1.00, confidence interval [CI] 0.88 to 1.13, intercept 0.94 mL/min/1.73 m2, CI -9.9 to 11.8, P=0.43). The within-individual coefficient of variation (CV) of the 240 min reference method was 5.4% at a mean GFR of 84.1 mL/min/1.73 m2. Single point estimates between 120 and 240 min had CVs of 4.5-7.0%, and did not differ from the reference method CV by more than 2.0 mL/min/1.73 m2. Two and three point estimates in the interval 60-120 min post iohexol injection offered no advantages over these single-point estimates and overestimated at lower GFRs. Conclusions: An iohexol clearance estimate of GFR derived from a single sample taken between 2 to 4 h after infusion may provide a suitable tool for routine clinical use.
Soft faeces excretion and passage time in the laboratory rabbit
Authors: Jilge B. 
Published: June 2007

Adult male rabbits, wearing a plastic collar to prevent coprophagy, excreted soft faeces during the first half of the light phase, starting at about the time the light switched on at 0600. While soft faeces were being excreted, food intake was reduced considerably in collared as well as in non-collared animals. Rate of passage of gastrointestinal contents in the rabbit was extremely high. Chromic oxide appeared in the faeces 4-5 h after it had been ingested in pelleted food. Coprophagy had no effect upon the rate of passage of gastrointestinal contents, and chromic oxide passed through at the same rate, whether it was incorporated in soft faeces or in pelleted diet.
Hepatitis and brain lesions due to mouse hepatitis virus accompanied by wasting in nude mice
Authors: Sebesteny A. , Hill A. C. 
Published: June 2007

Severe necrotising hepatitis, with microscopic brain lesions containing multi-nucleated giant cells, was observed in specified-pathogen-free nu-nu mice, contained in a semi-protected environment, but within the same room as other, conventional, mice. An entire group of 40 nu-nu mice died within a month, with no evidence of bacterial or parasitic infection. However, cell-free liver filtrates reproduced the liver lesions in specified-pathogen-free Swiss-Schneider mice injected intraperitoneally at up to 21 days of age, but not in baby rats and hamsters. Electronmicroscopy showed masses of particles resembling mouse hepatitis virus in the liver lesions of the recipient mice, and the identity of the virus was further confirmed serologically and by its physical properties. It was concluded that the infection was caused by a neurotropic variant of mouse hepatitis virus and could have originated from the conventional mice kept in the same room.
Sex factors in airborne infection: comparative susceptibility of male and female non-immunized mice to aerosolized Pasteurella multocida
Authors: Bouley G. , Dubreuil A. , Prulière D. , Bouley M. 
Published: June 2007

351 SPF OF1 non-immunized mice of both sexes were infected by aerosolized Pasteurella multocida. Female mice were significantly less susceptible to infection than were males of the same age (which were heavier). Males and females of equal bodyweight, but different age, showed no significant difference in susceptibility. The difference at equal ages can be explained by the lower respiratory flow of females. The consequences of these results for experimental studies on atmospheric pollutants are discussed.
Identification and genetic monitoring of mouse inbred strains using biochemical polymorphisms
Authors: Groen A. 
Published: June 2007

53 inbred strains and substrains of mice from 3 institutes in The Netherlands were examined at 12 chromosome loci coding body protein-polymorphism (Es-1, Es-2, Es-3, Es-S, Gpi-1, Hbb, Id-1, Ldr-1, Mpi-1, Mup-1, pgm-1, Trf). The allelic variation at 7 loci could be detected simultaneously. Within each institute most strains showed a unique combination of alleles at the 12 loci involved. Some nominally similar (sub)strains showed allelic divergence. One strain showed allelic variation at 4 loci. These findings emphasize the possibility and the necessity of monitoring the genetic purity of inbred strains of mice. A routine monitoring scheme using body protein-polymorphisms is proposed.
Some Aspects of the Physiology and Anatomy of the Cardiovascular System of the Ferret, Mustela Putorius Furo
Authors: Andrews P. L. R. , Bower A. J. , Illman O. 
Published: June 2007

Summary The resting heart rate was monitored in SO urethane-anaesthetized (387 ± 54 beats/min) and 4 conscious (341 ± 39 beats/min) ferrets. The arterial blood pressure in the anaesthetized animals was 140/110 ± 35/31 mmHg. The circulatory responses to vagal stimulation, carotid artery occlusion and a variety of humoral agents were examined. The vagal innervation of the heart and of the distribution of the great vessels are described.
Transmission of Spironucleus and Giardia Spp. and Some Nonpathogenic Intestinal Protozoa from Infested Hamsters to Mice
Authors: Sebesteny A. 
Published: June 2007

Summary Intestinal protozoa belonging to the genera Spironucleus (Hexamita), Giardia, Trichomonas and Entamoeba, carried by conventional hamsters, were successfully transmitted to and established in protozoa-free sucking or newly-weaned specified-pathogen-free inbred mice by exposure of the mice to hamster intestinal contents.
India-Ink Immunoreaction for Encephalitozoonosis: Phototechnique
Authors: Kellett B. S. , Bywater J. E. C. 
Published: June 2007

Summary We present photographs of an immunoreaction which has to be viewed as a wet preparation under high-power oil-immersion microscopy. The difficulties of varying focal plane and constant movement of the specimen were overcome by the use of electronic flash.