bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hypoxia, Hypocapnia and Spirometry at Altitude
Authors: Pollard Andrew J. , Barry Peter W. , Mason Nick P. , Collier David J. , Pollard Rachel C. , Pollard Peter F. A. , Martin Isla , Fraser R. Scott , Miller Martin R. , Milledge James S. 
Published: August 2015

1. Both hypoxia and hypocapnia can cause broncho-constriction in humans, and this could have a bearing on performance at high altitude or contribute to altitude sickness. We studied the relationship between spirometry, arterial oxygen saturation and end-tidal carbon dioxide (ETCO2) concentration in a group of healthy lowland adults during a stay at high altitude, and then evaluated the response to supplementary oxygen and administration of a β2 agonist
2. We collected spirometric data from 51 members of the 1994 British Mount Everest Medical Expedition at sea level (barometric pressure 101.2–101.6 kPa) and at Mount Everest Base Camp in Nepal (altitude 5300 m, barometric pressure 53–54.7 kPa) using a pocket turbine spirometer. A total of 205 spirometric measurements were made on the 51 subjects during the first 6 days after arrival at Base Camp. Further measurements were made before and after inhalation of oxygen (n = 47) or a β2 agonist (n = 39). ETCO2 tensions were measured on the same day as spirometric measurements in 30 of these subjects.
3. In the first 6 days after arrival at 5300 m, lower oxygen saturations were associated with lower forced expiratory volume in 1 s (FEV1; P &lt; 0.02) and forced vital capacity (FVC; P &lt; 0.01), but not with peak expiratory flow (PEF). Administration of supplementary oxygen for 5 min increased oxygen saturation from a mean of 81%–94%, but there was no significant change in FEV1 or FVC, whilst PEF fell by 2.3% [P &lt; 0.001; 95% confidence intervals (CI) −4 to −0.7%]. After salbutamol administration, there was no significant change in PEF, FEV1 or FVC in 35 non-asthmatic subjects. Mean ETCO2 at Everest Base Camp was 26 mmHg, and a low ETCO2 was weakly associated with a larger drop in FVC at altitude compared with sea level (r = 0.38, P &lt; 0.05). There was no correlation between either ETCO2 or oxygen saturation and changes in FEV1 or PEF compared with sea-level values.
4. In this study, in normal subjects who were acclimatized to hypobaric hypoxia at an altitude of 5300 m, we found no evidence of hypoxic broncho-constriction. Individuals did not have lower PEF when they were more hypoxic, and neither PEF nor FEV1 were increased by either supplementary oxygen or salbutamol. FVC fell at altitude, and there was a greater fall in FVC for subjects with lower oxygen saturations and probably lower ETCO2.
Clinical and Haemodynamic Sequelae of Deep Venous Thrombosis: Retrospective Evaluation after 7–13 Years
Authors: Janssen M. C. H. , Haenen J. H. , Van Asten W. N. J. C. , Wollersheim H. , Heijstraten F. M. J. , De Rooij M. J. M. , Thien TH 
Published: August 2015

1. In contrast to the extensive documentation on diagnosis and treatment of deep venous thrombosis (DVT), information about long-term complications, clike the post-thrombotic syndrome (PTS), is scarce. Most studies report on clinical examination only, whereas adequate haemodynamic investigation is lacking. Therefore 81 patients with venographically confirmed lower extremity DVT were clinically and haemodynamically reexamined 7–13 years after DVT (mean 10 years) to assess PTS. Interest was focused on the relation between clinical and haemodynamic PTS and the relation between location of the initial DVT and incidence of PTS.
2. Clinical signs and symptoms of PTS were classified according to the latest consensus of the international consensus committee on chronic venous disease. Non-invasive venous vascular laboratory tests were performed to assess the venous outflow resistance and calf muscle pump function (CMP). CMP was determined by the supine venous pump function test (SVPT).
3. Clinically only 20 of 81 patients (25%) were asymptomatic, 34 (42%) had mild PTS (class 1–3), 25 (31%) moderate PTS (class 4) and 2 (2%) severe PTS (class 5–6); 57% had an abnormal CMP. Both the severity of clinical symptoms and the haemodynamic abnormalities were related to the location of the initial thrombus. Of the patients with distal DVT 11% developed moderate clinical PTS and 39% developed an abnormal CMP. CMP and difference in CMP between post-thrombotic and non-thrombotic leg were significantly related to the different classes of PTS.
4. This study indicates that 7–13 years after DVT 31% of the patients had moderate and 2% had severe clinical PTS, while 57% of the patients had abnormal haemodynamic findings (both related to the initial site of the thrombosis). Secondly, it reveals that the risk of PTS after distal DVT is not negligible, which causes concern about not diagnosing and treating patients with distal DVT. Thirdly, we have demonstrated that a functional test, such as the SVPT, is a sensitive test to assess post-thrombotic damage. Therefore its use as a screening tool after a period of DVT should be investigated to select patients at risk of PTS.
Catamenial Variations in Erythrocyte Sodium–Lithium Countertransport and Blood Pressure
Authors: Adebayo G. I. , Hemeryck L. , Hall M. , Gasparro D. , Sinnott M. , Feely J. 
Published: August 2015

1. We undertook a temporal study of external sodium-stimulated lithium efflux (sodium—lithium countertransport) in erythrocytes and blood pressure by measuring these two parameters in three phases of the menstrual cycle (menstrual, midcycle and luteal phases) in 22 healthy, non-medicated females with regular menstrual cycles. Plasma oestradiol and progesterone levels were also determined.
2. Sodium—lithium countertransport activity (activity in 140 mmol/1 external NaCl) in the midcycle phase (0.176 ± 0.017 mmol h−1 l−1 of cells) was lower than in the menstrual (0.192 ± 0.016 mmol h−1 l−1 of cells, P &lt; 0.030) and luteal (0.203 ± 0.018 mmol h−1 l−1 of cells, P &lt; 0.030) phases. The Vmax of the transporter changed similarly but the Km was unaltered.
3. The plasma oestradiol level was 628.9 ± 39.1 pmol/1 in the midcycle phase, higher than in the menstrual (232 ± 18.5 pmol/1, P &lt; 0.001) and luteal (372.5 ± 28.1 pmol/1, P &lt; 0.001) phases. The progesterone level was 28.6 ± 2.1 nmol/1 in the luteal phase, and values were lower in the menstrual (2.5 ± 0.3 nmol/1, P &lt; 0.001) and midcycle (2.8 ± 0.4 nmol/1, P &lt; 0.001) phases.
4. There was no correlation between plasma oestradiol and sodium—lithium countertransport activity or Vmax during the menstrual cycle, but plasma progesterone was positively correlated with sodium—lithium countertransport activity (r = 0.478, P &lt; 0.025, n = 22) and Vmax (r = 0.551, P &lt; 0.045, n = 14) in the luteal phase.
5. Systolic blood pressure did not change significantly during the menstrual cycle. However, the diastolic pressure showed variation similar to that in sodium—lithium countertransport activity/Vmax, its midcycle value of 66.6 ± 1.4 mmHg being lower than that in the luteal (71.6 ± 1.3 mmHg, P &lt; 0.025) and menstrual (70.6 ± 1.4 mmHg, P &lt; 0.025) phases.
6. We conclude that sodium—lithium countertransport activity exhibits catamenial variation. Therefore we suggest, given this observation, that blood sampling for the assessment of the state of activity of the transport system be standardized in relation to a phase of the menstrual cycle in future studies involving females.
Protein Degradation during Renal Passage in Normal Kidneys is Inhibited in Experimental Albuminuria
Authors: Osicka Tanya M. , Comper Wayne D. 
Published: August 2015

1. Tritium labelled proteins, namely bovine serum albumin ([3H]BSA), rat serum albumin ([3H]RSA), anionic horseradish peroxidase ([3H]aHRP) and immunoglobulin present in urine fractions from rat filtration studies in vivo and isolated perfused rat kidneys (IPKs) have been shown by gel chromatographic analysis to be severely degraded to small peptides. The degradation of RSA and BSA in vivo has been shown to be similar.
2. Degradation of proteins in the urine from IPK experiments was inhibited by including 150 mmol/l lysine in the perfusate. Similarly, [3H]BSA and [3H]aHRP excreted from rats with puromycin aminonucleoside nephrosis was again essentially intact for both IPK and in vivo experiments.
3. It appears that the degradation of proteins observed in urine obtained from control kidneys is due, in part, to proteolytic activity associated with the proximal tubule. Inhibition of proximal tubule function, which occurs for both lysine and puromycin aminonucleoside treatments (as calibrated by lysozyme uptake), results in inhibition of the degradation observed. Glomerular epithelial cells could also contribute to the degradation.
4. There was no generation of low-molecular-weight material in the perfusate or plasma arising from breakdown of circulating proteins or recycling of potential degradation products from the tubules.
Hepatic Preservation with Histidine—Tryptophan—Ketoglutarate Solution in Living-Related and Cadaveric Liver Transplantation
Authors: Hatano Etsuro , Kiuchi Tetsuya , Tanaka Akira , Shinohara Hisashi , Kitai Toshiyuki , Satoh Seiji , Inomoto Takuya , Egawa Hiroto , Uemoto Shinji , Inomata Yukihiro , Lang Hauke , Oldhafer Karl J , Ringe Bruckhardt , Pichlmayr Rudolf , Tanaka Koichi , Yamaoka Yoshio 
Published: August 2015

1. Living-related liver transplantation has some advantages in the evaluation of novel clinical protocols, since many complicated factors affecting initial graft function are almost uniform in grafts obtained from healthy donors.
2. To compare histidine—tryptophan—ketoglutarate (HTK) and University of Wisconsin (UW) solution in terms of tissue oxygenation in living-related liver transplantation, oxygen saturation of haemoglobin (SO2) in hepatic tissue and its heterogeneity (CV, coefficient of variation) were measured by near-infrared spectroscopy. The HTK and UW groups consisted of 15 and 49 successful transplants respectively, in which no statistical differences in background were observed.
3. In the HTK group, hepatic SO2 after portal vein reflow was higher (P&lt;0.01) than that in the UW group, as was that after hepatic artery reflow (P&lt;0.05). In the UW group, hepatic SO2 remained at the lower level at the end of the operation.
4. Furthermore, the increase in CV after portal vein reflow was normalized after hepatic artery reflow in the HTK group. However, the CV remained at a high level at the end of the operation in the UW group.
5. Postoperative peak aspartate aminotransferase level in the HTK group was lower than that in the UW group (P&lt;0.05).
6. In cadaveric liver transplantation, higher hepatic SO2 and lower CV of hepatic SO2 in the early phase after reperfusion compared with the UW group (n = 18) were also observed in the HTK group (n = 30) (P&lt;0.05).
7. In conclusion, recovery of tissue oxygenation and its heterogeneity after reperfusion in HTK-preserved livers were more rapid and homogeneous than in UW-preserved livers in living-related liver transplantation. Accordingly, HTK solution may be a potential alternative to UW solution.
A Simple Versatile Method for Measuring Tail Cuff Systolic Blood Pressure in Conscious Rats
Authors: Widdop Robert E. , Li Xiao C. 
Published: August 2015

1. The non-invasive measurement of tail cuff systolic blood pressure in conscious rats is routinely used in long-term cardiovascular studies. There are a number of commercially available tail cuff systems, however, these apparatus are generally expensive and are dedicated for single-task operations. In the present study, a simple method for measuring systolic blood pressure, which requires only minor modifications to the existing hardware found in most cardiovascular laboratories, is described.
2. Systolic blood pressure measurements were made in the conventional manner by determining the systolic blood pressure which coincided with the restoration of the caudal artery pulse. This was achieved by using an inexpensive piezo-electric pulse transducer to detect the pulse, and this was coupled to a standard data-aquisition system (MacLab®, ADInstruments) normally set up to record blood pressure. This method was compared with another established tail cuff method, as well as with direct intra-arterial recordings.
3. It was found that the results obtained using both tail cuff systems were in good agreement when systolic blood pressure was measured in Wistar—Kyoto rats and spontaneously hypertensive rats. In addition, systolic blood pressure was measured over 4 weeks in 2K1C rats and sham-operated rats, with both tail cuff methods producing similar results, which were not significantly different from direct intra-arterial recordings in the same animals.
4. Thus, in the present study, with only minor modifications, the same equipment was used for both direct and indirect determinations of systolic blood pressure. This situation differs from other conventional tail cuff systems since these items are designed for a single purpose. Therefore, the current method using piezo-electric sensor/MacLab®-technology should be viewed as a relatively simple, flexible and cheap alternative method to measure tail cuff systolic blood pressure in conscious rats.
Nitric Oxide and Vascular Reactivity in Pregnant Rats with Adriamycin Nephropathy
Authors: Rathaus Mauro , Podjarny Eduardo , Benchetrit Sydney , Green Janice , Bernheim Jacques 
Published: August 2015

1. In previous studies we have shown that, after the administration of adriamycin, hypertension developed in rats who became pregnant (adriamycin-pregnant rats), whereas virgin animals remained normotensive. Subsequently, we showed that this hypertension was prevented by administration of l-arginine, suggesting that deficient synthesis of nitric oxide may be pathogenetic in this model.
2. To further assess the role of nitric oxide in this model, we measured mean arterial blood pressure after administration of l-arginine to adriamycin-pregnant rats or of NG-nitro-l-arginine-methyl ester (l-NAME) to normal pregnant rats. In other experiments, we assessed the response of isolated perfused arterial mesenteric vessels, precontracted with noradrenaline, to acetylcholine, l-arginine or l-NAME.
3. Blood pressure was decreased in normal pregnant rats, whereas it was elevated in adriamycin-pregnant rats. l-NAME treatment increased blood pressure in normal pregnant rats and l-arginine decreased it in adriamycin-pregnant rats.
4. Mesenteric vessels of adriamycin-pregnant rats exibited an exaggerated vasoconstrictory response to noradrenaline, when compared with the blunted response observed in normal pregnancy. The addition of l-NAME in vitro induced a further contraction, significantly greater in normal pregnant rats. The vasodilatory response to acetylcholine and l-arginine was greater in vessels from adriamycin-pregnant rats. In contrast, responses to either nitroprusside or diazoxide were similar in all groups.
5. The results suggest a state of reduced nitric oxide synthesis in rats with adriamycin nephropathy, leading to vascular maladaption and hypertension in pregnancy.
Evidence for an R(+)-[(dihydroindenyl)oxy]alkanoic Acid-Sensitive K+/Cl− co-Transporter in Human Platelets and its Interaction with the Na+/K+/2Cl− co-transporter
Authors: de Silva H. A. , Aronson J. K. 
Published: August 2015

1. The K+/Cl− co-transport system is activated by a number of interventions, such as cell swelling and stimulation with N-ethylmaleimide. It is specifically inhibited by R(+)-[(dihydroindenyl)oxy]alkanoic acid and requires the presence of K+ and Cl− on the same side of the cell membrane. This co-transporter has been studied extensively, mainly in erythrocytes of many species, in which it plays a key role in cell volume regulation. Here we present evidence that human platelets contain K+/Cl− co-transporters.
2. We have studied the efflux of 86Rb+ (a marker for K+) from 86Rb+-loaded human platelets, and have defined their response to stimulation by N-ethylmaleimide.
3. N-Ethylmaleimide (0.5 and 1 mmol/l) stimulated an increase in cumulative 86Rb+ efflux in a concentration-dependent manner. This efflux was inhibited by R(+)-[(dihydroindenyl)oxy]alkanoic acid (10 μmol/l) but was insensitive to bumetanide. It also required the presence of external Cl−.
4. These observations suggest that 86Rb+ efflux from the platelets stimulated by N-ethylmaleimide occurs via K+/Cl− co-transport.
5. When the K+/Cl− co-transporter was stimulated by N-ethylmaleimide we were unable to stimulate the Na+/K+/2Cl− co-transporter with a high external concentration of KCl or inhibit 86Rb+ efflux with bumetanide. Together with other evidence, this suggests that when the K+/Cl− co-transporter is stimulated with N-ethylmaleimide, the Na+/K+/2Cl− co-transporter is inhibited.
Age, Gender and Fractal Scaling in Heart Rate Variability
Authors: Otsuka Kuniaki , Cornelissen Germaine , Halberg Franz 
Published: August 2015

1. The fractal scaling of heart rate variability, gauged by the correlation dimension (CD), is hypothesized to be characterized by a time structure (chronome), which in health shows differences as a function of gender and age.
2. From 24 h Holter records of 44 clinically healthy male subjects in four age groups (5–10, 20–25, 40–45 and 60–65 years; n = 11 in each group), 500 s sections at 4 h intervals for 24 h were analysed for smoothed R-R intervals sampled at 4 Hz. Using an algorithm modified from Grassberger and Procaccia (Physica D 1983; 9: 189–208), the correlation integral was estimated for embedding dimensions from 1 to 20 with a 1.0 s time lag for each section. Nightly (02.00 hours-06.00 hours) ECG records were similarly analysed in 72 additional clinically healthy subjects of both genders, 5–70 years of age. The single cosinor assessed the circadian characteristics; one- and two-way analyses of variance and linear regression were used to examine changes as a function of gender and age.
3. The 24 h average of CD is largest in the 20–25-year-old men and decreases with age thereafter (P &lt; 0.05). These changes apply in particular to the nightly CD values, which are higher in female than in male subjects (P &lt; 0.001). Increasing age is associated with a decrease in the amplitude and an advance in the phase of the circadian rhythm in CD (P &lt; 0.05).
4. A chaotic end-point from fractal scaling, yielding a non-linear index, such as the correlation integral, undergoes a circadian rhythm and changes with gender and age. This assessment in the chronome represents an added diagnostic tool in cardiology, and provides new end-points for the study of coherence among internal variables of autonomic mechanisms and of influences by external environmental variables upon them.
Impaired Nitric Oxide-Mediated Vasodilatation and Total Body Nitric Oxide Production in Healthy Old Age
Authors: Lyons Declan , Roy Suzanne , Patel Mahesh , Benjamin Nigel , Swift Cameron G. 
Published: August 2015

1. Basal release of nitric oxide from the vascular endothelium maintains a constant vasodilating tone. Impaired nitric oxide-mediated vasodilatation has been described in hypertension and atheromatous disease. Circulatory diseases account for considerable morbidity and almost half of all deaths in people over the age of 75 years.
2. We have therefore compared nitric oxide-dependent vasorelaxation in 12 healthy elderly subjects with 12 young volunteers matched for blood pressure, cholesterol and glucose, using forearm occlusion venous plethysmography combined with brachial artery infusions of the nitric oxide synthase inhibitor, NG-monomethyl-l-arginine (l-NMMA; 1, 2 and 4 μmol/min) with noradrenaline (60, 120 and 240 pmol/min) as a control vasoconstrictor. We also measured urinary nitrate excretion after a controlled 48 h low nitrate diet as an index of total body nitric oxide production and correlated these changes with forearm blood flow responses to l-NMMA and noradrenaline in both groups.
3. The mean age and blood pressure of the elderly subjects was 76 (range 66–82) years and 132/76 (SEM 4/3) mmHg respectively, while in the young these were 27 (20–35) years and 131/72 (4/3) mmHg respectively. l-NMMA and noradrenaline produced dose-dependent reductions in forearm blood flow in both groups. l-NMMA (4 μmol/min) produced less vasoconstriction in the elderly than in the young (−37.7 ± 2.6 versus −48.3 ± 4.2%; P = 0.017). The mean slope of the l-NMMA dose-response curves in the elderly was significantly less than the younger group (−35.2 ± 3.1 versus −63.7 ± 10.6; P = 0.041). Noradrenaline, 240 pmol/min, also produced less vasoconstriction in the elderly compared with the young (−22.8 ± 2.9 versus −35.3 ± 5.0%; P = 0.029) although the slopes of the dose—response curves did not differ significantly.
4. Urinary nitrate adjusted for creatinine clearance was also significantly higher in the younger group (460.6 ± 97.7 versus 205.9 ± 64.8 μmol/day; P = 0.042) and showed a significant correlation with the percentage change in forearm blood flow in response to the maximum dose of l-NMMA (r = 0.5, P = 0.046).
5. We conclude that nitric oxide-mediated vasodilatation in the forearm vascular bed is diminished in old age and this reflects a more generalized reduction in nitric oxide production (as measured by urinary nitrate) in the circulation of older people. The blunted response to noradrenaline points to a more generalized reduction in vascular reactivity in the elderly.
Fractional Clearance of Albumin is Influenced by its Degradation during Renal Passage
Authors: Osicka Tanya M. , Panagiotopoulos Sianna , Jerums George , Comper Wayne D. 
Published: August 2015

1. The fractional clearance of intact albumin as determined by fractionation of urine by gel chromatography gave a value of 3.9 ± 1.6 × 10−4 for the isolated perfused kidney and 2.1 ± 0.6 × 10−4in vivo using ALZET osmotic pumps.
2. Albumin fractional clearance as measured by detection of the tritium label on the albumin molecule by radioactivity analysis gave a value of 7.5 ± 3.9 × 10−3 for the isolated perfused kidney and 2.3 ± 0.9 × 10−3in vivo.
3. The major differences between assays that detect intact albumin compared with non-specific assays in the estimates of the fractional clearance of albumin can be explained by the degradation of approx. 90% of albumin to small peptides during its renal passage. This has been demonstrated by size exclusion chromatography of urine samples from experiments where (i) exogenous tritium-labelled albumin was used in isolated perfused kidneys, (ii) exogenous tritium-labelled albumin was administered intravenously and (iii) analysis was made with metabolically labelled endogenous albumin in vivo.