bluuebunny/crossref_metadata_2025 huggingface dataset:
The endocrinology of pre‐eclampsia
Authors: Page N. M.
Published: March 2003

Pre‐eclampsia is a pregnancy specific syndrome that is a principal cause of maternal morbidity and mortality, accounting for almost 15% of pregnancy associated deaths, and is one of the major causes of iatrogenic prematurity among new born babies. The mild form of pre‐eclampsia most commonly presents with the features of maternal hypertension and proteinuria, but can swiftly and unpredictably become severe with numerous multisystem complications involving the maternal liver, kidneys, lungs, blood and platelet coagulation and nervous systems. The diverse symptoms of pre‐eclampsia have made it a difficult disease not only to define, but also to identify a causative agent for the symptoms. This review examines the complex endocrinological mechanisms believed to be responsible for the extensive complications of pre‐eclampsia from the role of placental and endothelial dysfunction, to the causes of the oxidative stress and the ensuing general inflammation. It also highlights current endocrine findings that exhibit the potential for clinical application, as either potential markers or novel therapeutic targets, with the aim of either preventing or altering the course of this life‐threatening disease of pregnancy.
Glucocorticoids as prophylaxis against acute mountain sickness
Authors: Basu M. , Sawhney R. C. , Kumar Surender , Pal K. , Prasad R. , Selvamurthy W.
Published: March 2003

Objective Acute mountain sickness (AMS) characterized by presence of symptoms including headache, nausea, excessive fatigue, loss of appetite, irritability and insomnia is a major impediment to work performance in human subjects who are rapidly inducted to high altitude (HA) during the initial phase of induction. The present study aims at to evaluate the efficacy of prophylactic administration of low dose glucocorticoids in prevention of AMS in normal healthy men who are inducted to HA by air.

Design Fifty healthy men were randomly divided into five groups of 10 each. Group I received prednisolone (Pred) 10 mg, Group II Pred 20 mg, Group III Pred 40 mg, Group IV dexamethasone 0·5 mg, Group V received placebo once a day in the morning for 2 days at sea level (SL) and for 3 days on arrival at an altitude of 3450 m by air.

Measurements The severity of AMS was assessed using Lake Louise AMS scoring system. Physiological parameters like blood pressure, respiratory rate, peripheral blood O2 saturation and heart rate were measured at sea level and on arrival at HA. Circulatory levels of cortisol and adrenocorticotropic hormone (ACTH) were measured by radioimmunoassay (RIA) and immunoradiometreic assay (IRMA), respectively.

Results In the placebo group, significant AMS could be detected at 12 h of arrival at HA, peaked by day 1 or 2 of stay and started declining thereafter. As compared to the placebo group, the steroid treated groups showed a significant (P < 0·01) reduction in daily AMS score. When compared with prednisolone 10 mg, 40 mg and dexamethasone groups, the prednisolone 20 mg group showed an optimal response in reduction of AMS symptoms. The O2 saturation showed a significant decline (P < 0·001) on arrival at HA, but the pattern of O2 saturation in placebo and glucocorticoid groups was identical. Similarly, the rise in heart rate and blood pressure and on day 3 of stay at HA was similar in placebo and glucocorticoid‐treated groups. An increase in plasma cortisol in placebo group was observed on day 3 of stay at HA and continued to rise till day 8 of observations. The cortisol levels in Pred 10 mg and Pred 20 mg groups on day 1 and 3 of arrival at HA were not significantly different than the SL post‐treatment values but were found to be significantly higher on day 8 of stay. Plasma cortisol in Pred 40 mg and dexamethasone groups was significantly lower (P < 0·01) on day 1 and 3 of stay but showed an increase by day 8 of stay. The ACTH levels were increased at HA in placebo group but did not show any significant change till day 3 of stay in steroid treated subjects and were found to be higher in all groups on day 8 of observations.

Conclusion These observations suggest that administration of low‐dose glucocorticoids can curtail acute mountain sickness significantly without influencing the normal adreno cortical response to hypoxia.
Comparisons of leptin, incretins and body composition in obese and lean patients with hypopituitarism and healthy individuals
Authors: Mersebach H. , Svendsen O. L. , Holst J. J. , Astrup A. , Feldt‐Rasmussen U.
Published: March 2003

objective To identify possible abnormalities specific for obesity in hypopituitary patients.

study design Cross‐sectional case–control study.

measurements and study subjects Body composition (DEXA) and measurements of fasting plasma levels of glucose‐dependent insulinotropic polypeptide (GIP), glucagon‐like peptides (GLPs), insulin, C‐peptide, glucose, leptin and lipids were performed in 25 hypopituitary patients (15 obese, 10 normal weight) and 26 BMI and age‐matched healthy controls (16 obese, 10 normal weight). All hypopituitary patients had GH deficiency and received adequate substitution therapy on this and other deficient axes (3 ± 1).

results Fasting GIP‐levels were significantly higher in obese hypopituitary patients compared to lean hypopituitary patients (P < 0·01), while the fasting concentrations of GLP‐1 and GLP‐2 were comparable between obese and lean hypopituitary patients. The same trend was seen in obese healthy controls vs. lean controls. No differences were observed in glucose, insulin or C‐peptide between the hypopituitary patients and the controls. Leptin levels were increased in obese hypopituitary patients compared to lean hypopituitary patients when adjusted for gender. At least a 2‐fold higher level of leptin was observed in women compared to men in both patient groups and healthy controls. Lean female hypopituitary patients had higher leptin levels than matched controls.

conclusions Fasting levels of GIP were elevated in obese substituted hypopituitary patients, while fasting concentrations of GLPs were similar. Obese hypopituitary patients had the same degree of hyperinsulinaemia, affected glucose tolerance, dyslipoproteinaemia and central obesity as obese healthy controls. Further studies are required to identify the possible biochemical reasons for obesity in patients with apparently well‐substituted hypopituitarism.
Lower leg electrical impedance after distal bypass surgery
Authors: Belanger  , Bolbjerg  , Heegaard  , Wiik  , Schroeder  , Secher
Published: March 2003

Electrical impedance was determined in 13 patients following distal bypass surgery to evaluate lower leg oedema as reflected by its circumference. Tissue injury was assessed by the plasma concentration of muscle enzymes. After surgery, the volume of the control lower leg increased from 1250 (816–2373) to 1384 (874–2345) ml (median and range; P<0·05), where the impedance did not change significantly from 140 (92–181) ohms. The volume of the operated leg increased more [from 1129 (824–2373) to 1600 (1090–2837) ml], and the decrease in electrical impedance was also pronounced [137 (125–169) to 83 (69–104) ohms (P<0·001)]. Tissue injury after surgery was indicated by an increase in total creatine kinase (n =  17) and MB isoenzyme of creatine kinase (n = 8) (P<0·05). Myoglobin (n = 8) had increased already during surgery (P<0·05), whereas there was no significant change in the plasma concentration of troponin I (n = 8). In conclusion, tissue injury was reflected by increases in muscle enzymes in plasma. We found an inverse correlation between lower leg electrical impedance and volume, but the deviation in electrical impedance was approximately twice that of the leg volume. Electrical impedance appears to be a useful method for the evaluation of lower leg oedema after distal bypass surgery.
Diagnostic role of residual volume in paediatric patients with chronic symptoms of the lower airways
Authors: Walamies
Published: March 2003

In bronchial asthma, measurement of absolute lung volumes may reveal lung dysfunction more readily than forced expiratory spirometry. Sixty‐one children (aged 4–16 years) with mild to moderate bronchial asthma and 35 children (aged 7–16 years) with other symptoms of the lower airways (OSLA) were studied, and the plethysmographic results were compared with data obtained from 36 healthy volunteers aged 6–16 years. In the first test session, repeatability of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), residual volume (RV), functional residual capacity (FRC) and total lung capacity (TLC) were good. Control subjects were also tested the next day, and intra‐subject variability of repeat pulmonary function testing was in the normal range. The FEV1/FVC ratio was significantly higher in control subjects than in patients with asthma or OSLA, but only the decrease in RV after bronchodilator challenge separated patients with asthma from patients with OSLA. Changes in FEV1 and RV after bronchodilator challenge had a significant, although low, inverse correlation. An increase of ≥ 5% in FEV1 had a positive predictive value of 44% and a negative predictive value of 68% for the clinical diagnosis of bronchial asthma; for a decrease of  ≥ 24% in RV, the figures were 86% and 71% respectively. The support of baseline absolute lung volumes on clinical decision‐making is not necessarily great. Bronchodilator response, particularly in RV, is more pertinent and may enhance the detection of reversible lung dysfunction.
Methodological aspects of the evaluation of endothelium‐dependent vasodilatation in the human forearm
Authors: Lind  , Sarabi  , Millgård
Published: March 2003

The present study, involving 56 healthy subjects from a health screening, was undertaken to address some methodological questions regarding the measurement of endothelial function using local intra‐arterial infusions of metacholine (2 and 5 μg min−1) to evaluate endothelium‐dependent vasodilatation, and sodium nitroprusside (SNP, 5 and 10 μg min−1) to evaluate endothelium‐independent vasodilatation. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. The ratio of FBF during the highest dose of metacholine to FBF during the highest dose of SNP was used as an index of endothelial function. In 10 young volunteers the procedure was repeated after 2 h and again after 3 weeks in order to study short‐term and long‐term reproducibility of the method.

Neither the vasodilatatory response to metacholine (r = 0·006) nor that to SNP (r = 0·08) was related to resting FBF. Neither the circumference nor the length of the arm was related to endothelial function (r = 0·01−0·11), as evaluated by the FBF on metacholine to nitroprusside ratio (mean 1·3 ± 0·3 SD).

The use of a wrist cuff to exclude hand circulation, or not, did not influence the evaluation of endothelial function significantly.

Maximal FBF after 3 min of arterial occlusion of the forearm was significantly related to blood flow during both metacholine (r = 0·53, P < 0·01) and nitroprusside infusion (r = 0·36, P < 0·05), but not to the FBF on metacholine to nitroprusside ratio (r = 0·01).

The short‐term and long‐term reproducibility of FBF during vasodilatation with metacholine and SNP was good (r = 0·89−0·97, P < 0·001), while the individual measurements for resting FBF were less reproducible when repeated after 3 weeks (r = 0·34).

In conclusion, endothelial function was not related to resting FBF, nor to the arm circumference or length. No major difference was seen whether endothelial function was evaluated with or without exclusion of the hand circulation. Maximal FBF during reactive hyperaemia was not related to endothelial function.
The diagnostic value of oesophageal radionuclide transit in patients admitted for but without acute myocardial infarction
Authors: Jørgensen  , Fruergaard  , Launbjerg  , Aggestrup  , Elsborg  , Hesse
Published: March 2003

The use of radionuclide transit (RT) as a screening test for chest pain of oesophageal origin has been debated. The aim of this study was to determine the value of RT as a screening test for oesophageal disorders in comparison with oesophageal manometry in patients admitted with acute chest pain but without acute myocardial infarction (non‐AMI patients), and to assess the frequency of oesophageal disease present in these patients. A total of 222 non‐AMI patients entered the study. An extensive examination programme comprised noninvasive cardiac studies, pulmonary studies, a careful physical examination of the musculoskeletal system, and oesophago‐gastric examinations including endoscopy, pH monitoring of the oesophagus and a Bernstein test. In 91% of the patients one or more diagnoses were obtained.

Based on clinical and laboratory data a `consensus' diagnosis was made. With manometry as the reference RT had a poor sensitivity (35%) but an acceptable specificity (82%). With the consensus diagnosis as the gold standard the sensitivities of both manometry and RT were poor (29%), whereas the specificity of RT, but not of manometry, was very high (97%). Gastrointestinal diagnoses were found in 57% of the patients. In conclusion, none of the applied oesophageal examinations are valuable as single screening tests. Both RT and manometry have low sensitivities. RT may be used as a cheap, noninvasive and rapid supplementary examination. When positive, it strongly supports further invasive studies of the oesophagus in non‐AMI patients with unexplained chest pain.
Reproducibility of oximetry with a static charge‐sensitive bed in evaluation of obstructive sleep apnoea
Authors: Lojander  , Salmi  , Maasilta
Published: March 2003

The reproducibility of overnight polygraphic recording with oximetry, the use of a static charge‐sensitive bed (SCSB), thermistors and a body position sensor was assessed in diagnosing obstructive sleep apnoea syndrome (OSAS). Forty‐six patients with a clinical suspicion of OSAS underwent a repeat recording. No treatment for OSAS and no change in patient characteristics was allowed between duplicate nights. Between repeated recordings significant correlations were found for ODI4, time spent at Sa
O2 < 90% and the mean nadir Sa
O2. Good agreement was found in concordance of classification of ODI4, time spent at Sa
O2 < 90% and body movements. The combination of oximetry, thermistors, SCSB and body position sensor has a good reproducibility as an affordable screening method in the evaluation of OSAS.
Posturally induced leg vasoconstrictive responses: relationship to standing duration, impedance and volume changes
Authors: Mayrovitz H. N.
Published: March 2003

Shifting legs to a gravity‐dependent position provokes a physiological vasoconstrictive response that forms the basis of several diagnostic tests based on initial (< 5 min) blood perfusion decreases. However, it is not known if responses are maintained over longer duration and if they depend on the volume shifted to the limb during the manoeuvre. These issues were investigated by measurements of blood perfusion changes on foot and ankle (laser Doppler) and below‐knee volume and impedance changes induced by 30 min of standing in 10 healthy volunteers. Initial perfusion decreases were 66·4% ± 2·6% and 49·3% ± 3·8% for ankle and foot dorsum, respectively, and were fully maintained during sustained standing without evidence of `vasodilator escape'. Response magnitudes were not dependent on leg volume changes using geometric or impedance measures. A close correlation (r2 = 0·78) between impedance and volume changes suggests the former as a useful way of assessing dynamic limb volume changes. Sustained vasoconstrictive responses make it unlikely that extending the duration of such tests would offer more diagnostic information than is currently available.
Apnoea‐associated heart rate changes among preterm and full‐term infants exposed to hyperthermia
Authors: Tirosh Emanuel , Bader David , Hodgins Hadar , Cohen Ayala , Tal Yoram
Published: March 2003

Heart rate (HR) changes associated with apnoea (>3 s) were analysed in 10 preterm infants (30·6 ± 1·5 weeks) at post‐conceptional age of 40 ± 1·5 weeks and 10 full‐term (FT) infants (39 ± 1 weeks) before, during and after exposure to increased environmental temperature (5°C above normothermia). A significantly increased HR was found in the study group during the baseline (normothermia), heating, cooling and final normothermic phase compared with the control infants. No significant difference was found between the groups during the hyperthermic stage. A significant relative increase in HR was found among the preterm infants but not among FT infants during central apnoea at the hyperthermia phase. Our results indicate that HR control during apnoea in preterm infants is more labile then among FT infants while being exposed to increased environmental temperature.
Determination of blood flow in the finger using near‐infrared spectroscopy
Authors: Rendell Marc , Hovelson Chad , O'Connor Kelly , Cheung Lance , Huard Scott , Kong Tae‐Sok , Catania Anthony , Rosenthal Robert
Published: March 2003

Wavelengths in the near‐infrared range have much better penetrance in organic substances than visible light. We used near‐infrared spectroscopy to determine non‐invasively blood flow in the fingertip. We used laser Doppler technology to measure skin blood flow as a comparison procedure. We performed several manoeuvres to change blood flow. These included restriction of flow, thermal stimulation and post‐occlusion hyperaemia. Near‐infrared measurements had coefficients of variation of 10–15% at the various wavelengths, contrasting with variability of 30–40% with laser Doppler measurement. With restriction of blood flow, there was a downward shift in the absorbance curve. With thermal stimulation and with post‐occlusion hyperaemia, there was a rise in the curve. The flow‐induced shifts in the absorbance curve were particularly pronounced in the range of 850–970 nm. The correlation between absorbance values and laser Doppler‐determined blood flow was also highest in this range, averaging about 0·69 (n = 625). Near‐infrared spectroscopy can therefore be used to scan the fingertip. The absorbances obtained do reflect changes in blood flow. There is a correlation with skin blood flow, although near‐infrared measurements are affected by blood flow in the full breadth of the finger, not just the skin. We can measure this blood flow with significant reproducibility. It may be possible to use near‐infrared spectroscopy to measure the concentration of individual blood components.
Non‐linear cardiac dynamics and morning dip: an unsound circadian rhythm
Authors: Yum Myung‐Kul , Kim Nam‐Su , Oh Jae‐Won , Kim Chang‐Ryul , Lee Jae‐Woong , Kim Soon‐Kil , Noh Chung‐Il , Choi Jung‐Yun , Yun Yong‐Soo
Published: March 2003

The frequency of sudden cardiac death increases in the morning. The relationship between decreased complexity of heart rate dynamics and sudden cardiac death has been documented. An understanding of circadian variation in the complexity of cardiac dynamics may be important to predict and prevent sudden cardiac death. Dynamic 24‐h electrocardiographic recordings were obtained from 30 healthy ambulant subjects aged 41–50 years, and the digitized data were partitioned into sections of 30 min duration. For each section, four indexes obtained from separate algorithms of non‐linear dynamics of the RR interval – modified correlation dimension, Lyapunov exponent, approximate entropy, and fractal dimension – were calculated. Normalized low‐ (0·04–0·15 hertz) and high‐frequency (>0·15 hertz) components were also calculated. All four indexes of non‐linear dynamics showed a remarkably similar circadian rhythm: a prominent morning dip preceded by a steep decline during the late night, a recovery during the evening and a peak around midnight. In the morning, the low‐frequency component rose rapidly with concomitant reduction in the high‐frequency component. The complexity of cardiac dynamics decreases significantly in the morning, and this may contribute to the ominously increased rate of cardiac death in the morning hours.
Early autonomic dysfunction in patients with diabetes mellitus assessed by spectral analysis of heart rate and blood pressure variability
Authors: Laederach‐Hofmann  , Mussgay  , Winter  , Klinkenberg  , Rüddel
Published: March 2003

Patients with diabetes mellitus (DM) often have alterations of the autonomic nervous system (ANS), even early in their disease course. Previous research has not evaluated whether these changes may have consequences on adaptation mechanisms in DM, e.g. to mental stress. We therefore evaluated whether patients with DM who already had early alterations of the ANS reacted with an abnormal regulatory pattern to mental stress. We used the spectral analysis technique, known to be valuable and reliable in the investigation of disturbances of the ANS. We investigated 34 patients with DM without clinical evidence of ANS dysfunction (e.g. orthostatic hypotension) and 44 normal control subjects (NC group). No patients on medication known to alter ANS responses were accepted. The investigation consisted of a resting state evaluation and a mental stress task (BonnDet). In basal values, only the 21 patients with type 2 DM were different in respect to body mass index and systolic blood pressure. In the study parameters we found significantly lower values in resting and mental stress spectral power of mid‐frequency band (known to represent predominantly sympathetic influences) and of high‐frequency and respiration bands (known to represent parasympathetic influences) in patients with DM (types 1 and 2) compared with NC group (5·3 ± 1·2 ms2 vs. 6·1 ± 1·3 ms2, and 5·5 ± 1·6 ms2 vs. 6·2 ± 1·5 ms2, and 4·6 ± 1·7 ms2 vs. 6·2 ± 1·5 ms2, for resting values respectively; 4·7 ± 1·4 ms2 vs. 5·9 ± 1·2 ms2, and 4·6 ± 1·9 ms2 vs. 5·6 ± 1·7 ms2, and 3·7 ± 2·1 ms2 vs. 5·6 ± 1·7 ms2, for stress values respectively; M/F ratio 6/26 vs. 30/14). These differences remained significant even when controlled for age, sex, and body weight. However, patients with DM type 2 (and significantly higher body weight) showed only significant values in mental stress modulus values. There were no specific group effects in the patients with DM in adaptation mechanisms to mental stress compared with the NC group. These findings demonstrate that power spectral examinations at rest are sufficiently reliable to diagnose early alterations in ANS in patients with DM. The spectral analysis technique is sensitive and reliable in investigation of ANS in patients with DM without clinically symptomatic autonomic dysfunction.
A fractal approach for evaluation of pulmonary circulation in man at rest and during exercise
Authors: Kuikka  , Länsimies
Published: March 2003

Changes in pulmonary circulation caused by muscular exercise and body position are usual in daily life. By using first‐pass radiocardiography and fractal analysis, pulmonary circulation in man was evaluated at rest and during muscular exercise. At rest, pulmonary circulation was heterogeneous as described by the relative dispersion (which is the coefficient of variation, i.e. the standard deviation of the pulmonary transit times divided by the mean transit time; RD = 0·51 ± 0·06) and fractal in nature. During exercise, pulmonary circulation became more homogeneous (RD = 0·35 ± 0·04; P<0·001). The calculated fractal dimension decreases from 1·09 at rest to 1·06 during exercise. The model identifies a cubic‐law response for circulation heterogeneity and a quarter‐power law for resistance during muscular exercise.
Influence of orthopaedic metal and high‐density detection on body composition as assessed by dual‐energy X‐ray absorptiometry
Authors: Madsen  , Egsmose  , Lorentzen  , Lauridsen  , Sørensen
Published: March 2003

We examined the influence of orthopaedic material and computerized high‐density detection (HDD) on analysis of bone mass and soft tissue composition performed by dual‐energy X‐ray absorptiometry (DXA). Measurements of total and regional bone area, bone mineral content (BMC), areal bone mineral density (BMD), lean tissue mass (LTM) and fat tissue mass (FTM) were made using a Norland XR‐26 DXA scanner with dynamically changing samarium filtration. Twenty‐one subjects who were free of metal implants were measured without and with a Biomet femoral prosthesis (titanium) placed on the proximal part of the femoral region. Twenty‐one women with an endogenous prosthesis in the proximal femur were measured once. Analyses of tissue composition were performed without and with HDD using software provided by the manufacturer. Measurements were considerably affected by exogenous metal with overestimation of LTM and underestimation of FTM and bone area. BMC and BMD were over‐ or underestimated depending on the anatomical region. Enabling the HDD mode, values of bone area and tissue mass came closer to the expected values (–metal/–HDD) but were in general still significantly different from these. For the total body, the following significant changes were found after application of metal (+metal/–HDD vs. +metal/+HDD, mean values): bone area –19·8% vs. –6·9%, BMC +1·1% vs. –2·1%, BMD +26·5% vs. +4·7%, LTM +12·4% vs. +3·7%, FTM –15·8% vs. –7·0%. A similar pattern of change in tissue composition and bone area was found for the subregions of the body. Changes in tissue composition after HDD were similar in subjects with exogenous and endogenous metal, indicating that the experimental model was appropriate. In conclusion, measurements of tissue composition were substantially influenced by orthopaedic metal. HDD partly corrected for the artefacts induced by the metal.
Common slow modulation of respiration, arterial blood pressure and cortical activity during sleep onset while napping
Authors: Rittweger Jörn
Published: March 2003

Using healthy subjects, concomitant 30‐ to 60‐s modulations of respiration, arterial blood pressure and EEG activity were found in 21 experiments about napping. Although mean arterial pressure (MAP) modulations above and below 1/30 Hz increased, in respiratory amplitude (RA) only the lower frequency components augmented significantly. This slow modulation of RA was found to be asymmetrical in time, the duration of RA decreasing parts in the modulation waves being 42% longer than the duration of RA increasing parts. The concomitance of the slow modulations in the different organ systems is accounted for by the influence of the common brainstem system (CBS), which regulates and integrates respiratory, cardiovascular and somatomotor systems and the adjustment of central nervous activity (vigilance). The described common, slow modulations outline the importance of dampening influences during sleep onset. They may provide an important tool for the investigation of the regulatory systems during sleep onset, as well as for investigations about sleep apnoea syndrome and Cheyne–Stokes breathing.
The effect of arginine vasopressin, lysine vasopressin or oxytocin on ADP or arginine vasopressin‐induced Ca2+ increase in human platelets
Authors: Pedersen Odd S. , Reichelt KarL. L.
Published: March 2003

Oxytocin (OT), lysine vasopressin (L8VP), arginine vasopressin (A8VP) or arginine vasotocin (A8VT) are found in plasma from several species and stimulate various cell types by activation of the polyphosphoinositide metabolism and mobilization of intracellular calcium. We therefore studied the effects of the nonapeptides OT, A8VT, L8VP or A8VP on cytoplasmic calcium (Ca2+) and the effect of the nonapeptides on A8VP‐induced Ca2+ mobilization. The preincubation of platelets with ‘physiological’ concentrations of A8VP (2–4 pmol l–1) did not enhance the intracellular calcium increase caused by the agonists used. However, the ADP‐induced calcium increase was enhanced by prior addition of subthreshold concentrations of A8VP (less than 1 nmol l–1) to the platelet suspension (by 10%, P=0·027, n=12). Neither OT nor A8VT in concentrations from 10–5 μmol l–1 to 1 μmol l–1 increased the cytoplasmic calcium concentration. We found that both OT and A8VT blocked the effect of subsequent exposure to A8VP. ADP (0·4 μmol l–1) did not block the effect of A8VP.
Comparison of resting energy expenditure measurements by ventilated canopy and by respiration chamber
Authors: Kistorp Caroline Nervil , Toubro Søren , Astrup Arne , Svendsen Ole Lander
Published: March 2003

The study compared measurements of resting energy expenditure (REE) by two methods, namely the commercially available ventilated canopy (Medgraphics CCM system) and the respiration chamber. Thirty‐five healthy subjects of both sexes with a wide weight range (BMI 18–33·8 kg m−2) were measured on both systems. The linear regression equation was REEcanopy=0·66 × REEresp.cham. + 61·1 (kJ h−1), and the corresponding SEE% was 8·6%. The correlation was high (r=0·89). However, the mean REE measured using the ventilated canopy was 41 kJ h−1 (13%) lower than that using the respiration chamber (P<0·01). The Medgraphics CCM canopy system seems valid for measurements of REE. However, the REE results measured by the canopy were systematically lower than when measured by the respiration chamber, but can be converted by the equation given with an accuracy error of 9%.
Hip fracture discrimination by imaging ultrasound measurements of the calcaneus
Authors: Prins  , Lauritzen  , Jørgensen  , Simonsen  , Hassager
Published: March 2003

Quantitative ultrasound measurements of the os calcis have recently been upgraded with imaging facilities. This has made measurements of a specific region of interest possible and improved the reproducibility of the method, but the diagnostic ability of imaging ultrasound has not yet been investigated thoroughly. We measured broadband ultrasound attenuation (BUA) and speed of sound (SOS) using imaging ultrasound as well as forearm bone mineral density (BMDarm) using dual‐energy X‐ray absorptiometry in three age‐matched groups of women: (1) 25 women who were admitted to hospital due to a hip fracture; (2) 23 women who were admitted to hospital due to a fall without any fracture; and (3) 26 normal women. Furthermore, BMD of the hip (BMDhip) was measured in a subgroup of the hip fracture patients and those who had fallen. All measurements were performed during the index hospitalization in order to avoid any influence from bone loss due to immobilization after the fracture. We found a –0·48 SD deviation from expected age‐matched values in BUA among the hip fracture patients, whereas the patients who had fallen showed a +0·16 SD deviance. For SOS, the figures were –0·70 SD for the hip fracture group and –0·06 SD for the patients who had fallen. For BMD of the arm we found values of –0·65 SD and +0·08 SD, respectively, whereas the figures for BMD of the hip were –0·66 SD and +0·13 SD, respectively. All parameters were significantly lower in the hip fracture group compared with the patients who had fallen. None of the parameters in the patients who had fallen deviated significantly from expected normal age‐matched values. Neither BMD of the arm or BMD of the hip separated hip fracture patients and patients who had fallen significantly better than ultrasound (BUA or SOS) did. We conclude that imaging ultrasound (BUA or SOS) separates age‐matched groups of hip fracture and non‐fracture patients as well as BMD measurements do.
Changes in airway dead space in response to methacholine provocation in normal subjects
Authors: Olsson  , Greiff  , Karlefors  , Johansson  , Wollmer
Published: March 2003

Measurements of bronchial hyper‐responsiveness rely on sensitive techniques for measurement of bronchoconstriction, ideally based on tidal breathing. A potentially useful technique is measurement of airway dead space (VDaw), which reflects the volume of the conducting airways. The aim of this study was to evaluate measurements of VDaw with the single breath test for CO2 (SBT‐CO2), compared to spirometric measurements, as a method of measuring bronchial response to methacholine challenge. Nineteen healthy adults were studied. Dosimetric methacholine challenge tests were performed on two study days. Forced expirations or the SBT‐CO2 were used to assess the response. There were dose‐dependent reductions in the spirometric measurements, with a 10 ± 10% reduction from the baseline value of forced expiratory volume at the highest dose of methacholine. There was a dose‐dependent reduction from the baseline value of VDaw by 19 ± 9% at the highest dose. There was also a dose‐dependent increase in the slope of the alveolar plateau of the SBT‐CO2. This study provides support for measurement of VDaw as a means of evaluating bronchial responsiveness after methacholine challenge. In a group of healthy adults, this method shows a greater response but with similar dispersion as measurement of forced expiratory volume after methacholine challenge.
Assessment of intermittent claudication: a comparison of questionnaire, visual analogue scale and subjective estimate information with post‐exercise ankle–brachial pressure index
Authors: Peräkylä Tarja , Lindholm Harri , Lepäntalo Mauri
Published: March 2003

In order to assess two simple methods of evaluation of claudication, a standard questionnaire and visual analogue scale, a comparison was made between them and the post‐exercise pressure index used as a gold standard. Fifty‐eight consecutive stable claudicants were recruited to the study, 51/58 having arterial insufficiency according to post‐exercise pressure measurements. Both methods appeared to correlate rather poorly with post‐exercise pressures. Thus visual analogue scale cannot be used alone to assess walking tolerance but as it offers qualitative information it may be used to supplement pressure measurements in the assessment of incapacity caused by intermittent claudication.
Rhythms and complexity of respiration during sleep in pre‐term infants
Authors: Patzak  , Schlüter  , Mrowka  , Unbehaun  , Gerhardt  , Persson  , Barschdorff  , Trowitzsch
Published: March 2003

The aim of this study is to test rhythmic and complex properties of respiratory control in former ventilated, pre‐term infants during quiet and active sleep. The children had a higher risk for sudden infant death due to bronchopulmonary dysplasia (BPD). Twelve infants suffering from BPD and 12 control infants, matched regarding their post‐conceptional age, were examined polygraphically during quiet (QS) and active sleep (AS). The respiratory rate (RR), the ratio (LF/HF) between the low‐frequency power (LF) and the high‐frequency power (HF) of the spectra of the thoracic respiratory effort, and the frequency of the dominant peak within LF (LFF) and HF (HFF) were computed. The correlation dimension (D2) of the respiratory signal was calculated to determine the complexity of the respiratory control. The transcutaneous pO2 (tcpO2) and pCO2 and the oxygen saturation (sO2) were analysed. Infants with BPD had significantly higher RR and HFF during QS (median: BPD 48 breaths min–1; control 32 breaths min–1). tcpO2 and sO2 were significantly lower in the BPD group. No differences were found in LF/HF, LFF or D2 between groups, either in QS or in AS. D2 ranged between 1·8 and 3·8, showing significantly higher values during AS. LFF was found to be lower during active sleep (AS 0·04–0·05 Hz; QS about 0·06 Hz). We propose that in infants with BPD the lower lung compliance and the higher resistance, and possibly also the hypoxaemia, contribute to the acceleration of breathing. The behaviour of RR, spectral parameters and D2 indicates a specific, functional setting rather than a regulatory impairment in infants with BPD.
The effect of high‐ and low‐frequency H‐wave therapy upon skin blood perfusion: evidence of frequency‐specific effects
Authors: McDowell  , McElduff  , Lowe  , Walsh  , Baxter
Published: March 2003

The current study was designed to assess the putative physiological effects of H‐wave therapy (HWT, a mode of therapeutic electro‐stimulation) on skin blood flow in humans and to determine the relevance of frequency to any such effects. Laser Doppler flowmetry was used to record changes in blood perfusion on the dominant forearm of healthy human volunteers (n=36), who were each assigned, under randomized double blind conditions, to one of three experimental groups: placebo or HWT at 2 or 60 Hz. HWT stimulation was applied for 20 min, during which time concomitant skin temperature was recorded using three surface skin thermistors. Statistical analysis of perfusion measurement and skin temperature changes pre‐, during and for up to 18 min post‐HWT stimulation showed a highly significant increase in skin blood flow in the 2 Hz group when compared to placebo and 60 Hz (P ≤ 0·01). This was associated with a significant increase in skin temperature during the period of stimulation (P ≤ 0·05). No such differences were observed in the 60 Hz group. These results provide evidence that low‐frequency HWT may produce direct localized effects on cutaneous blood flow, a finding relevant for clinicians working in the field of tissue repair.
Regional V˙A/Q˙ ratios in man using 133Xe and single photon emission computed tomography (SPECT) corrected for attenuation
Authors: Almquist  , Jonson  , Palmer  , Valind  , Wollmer
Published: March 2003

We describe a technique to obtain non‐invasively regional pulmonary ventilation–perfusion ratios (V˙A/Q˙) using single photon emission computed tomography (SPECT) and continuous infusion of 133Xe. Single photon transmission tomography was used for attenuation correction, for delineation of the lungs and for V˙A/Q˙ calculations. Data are presented for six normal subjects and compared to those for two patients with moderate chronic obstructive pulmonary disease (COPD). The mean V˙A/Q˙ for the whole lung of the normal subjects ranged from 0·49 to 0·65, group mean 0·56 ± 0·07 (1 SD), and there was no significant difference between the right and left lung. The consistently too low V˙A/Q˙ values are related to the inability to measure regional blood volume and the low resolution of the scintillation camera, giving an under‐estimation of tracer input. For the normal subjects, the dispersion of V˙A/Q˙, as defined by the standard deviation of the individual distribution functions, ranged from 0·12 to 0·19. One of the patients was characterized by a low mean V˙A/Q˙ of 0·35, and the other patient had a wide dispersion (SD) of V˙A/Q˙ of 0·37. In the normal subjects, a consistent V˙A/Q˙ gradient was found only in the ventrodorsal direction. 133Xe and SPECT can be used to obtain meaningful biological information regarding ventilation/perfusion relationships of potential clinical value.
Reliability of position sense testing assessed with a fully automated system
Authors: Lönn  , Crenshaw  , Djupsjöbacka  , Johansson
Published: March 2003

Position sense testing has increased as a tool for augmenting evaluation of joint injury. In the present study, we investigated the inter‐day reliability for four different types of position sense tests using a fully automated system. The tests included (1) passive presentation/active replication, (2) passive presentation/passive replication, (3) semi‐passive presentation/semi‐passive replication (where semi‐passive denotes passive movement during antagonist muscle contraction), and (4) active presentation/active replication. The absolute difference between presented target and replicated position was used as a measure of position sense accuracy. Ten healthy subjects who were blindfolded and seated with the arm in a moveable rig performed the tests on two occasions, separated by 3–4 days. For each type of position sense test, horizontal abduction from a starting position of 0° (relative to the sagittal plane) to target positions of 32° and 64°, and horizontal adduction from a starting position of 80° to 48° and 16° were conducted. A two‐way ANOVA revealed no differences in absolute error between days or between testing procedures. However, intra‐class correlations (ICC), which are most often used to express test–retest reliability, were moderate at best, ranging from 0·40 to 0·61 for the four types of position sense tests. Hence, the present study indicates that the ability of repositioning tests to detect alterations in proprioceptive function is limited, suggesting that their use in clinical evaluation be approached with prudence.
Beat‐to‐beat QRS amplitude variability in elite endurance athletes
Authors: Landelius  , Norinder  , Svedenhag  , Nowak  , Sylvén
Published: March 2003

Results from variance electrocardiography, displaying the wide‐band, phase‐locked electrical micro‐variability during the depolarization phase, was analysed versus clinical data, echocardiographic structural and functional variables and myocardial scintigraphic findings in 174 elite orienteers compared with 37 age‐matched elite endurance athletes and 50 age‐matched, healthy medical students. PCA analysis identified a subgroup of five orienteers deviating from the rest of the study group and both control groups with regard to their QRS amplitude variability. No correlations were found between pathology by medical history or any of the echocardiographic and scintigraphic variables or by the variance electrocardiographic aberrations in any of the groups studied.
Muscle glycogen does not interfere with a 13CO2 breath test to monitor liver glycogen oxidation
Authors: Tanis  , Rietveld  , Wattimena  , Van Den Berg  , Swart
Published: March 2003

Naturally 13C‐enriched carbohydrate has been used to label the liver glycogen pool for metabolic studies. The utilization of this glycogen was then monitored by the appearance of 13CO2 in breath. Using this method, it is assumed that during sedentary fasting the contribution of muscle glycogen towards oxidation is negligible. We investigated the influence of a different level of 13C enrichment of muscle glycogen on the 13C enrichment of breath CO2 while the breath test was carried out. In six healthy volunteers, the muscle glycogen stores were grossly depleted by a cycling exercise prior to consumption of the 13C‐enriched diet which was given over a 10 h period. The oxidation of liver glycogen was measured during an 18 h sedentary fast. The results were compared with a control group who had not depleted their muscle glycogen before labelling. A higher 13C enrichment of muscle glycogen did not interfere with two parameters of liver glycogen oxidation, i.e. the duration of the plateau phase of 13CO2 and the return to baseline time. It was also shown that the 13C‐labelled muscle glycogen was still available after the 18 h fast because a strenuous exercise led to a rapid 13CO2 enrichment. It is concluded that muscle glycogen 13C enrichment does not invalidate a 13CO2 breath test to measure liver glycogen oxidation during a sedentary fast.
Evaluation of endothelium‐dependent vasodilation in the human peripheral circulation
Authors: Lind Lars , Hall Jan , Larsson Anders , Annuk Margus , Fellström Bengt , Lithell Hans
Published: March 2003

Flow‐mediated vasodilation (FMD) in the brachial artery measured by ultrasound, and the increase in forearm blood flow (FBF) induced by local infusion of a muscarinic‐receptor agonist have both frequently been used to evaluate endothelium‐dependent vasodilation (EDV) in the human forearm. The present study intended to evaluate the relationship between these techniques and to investigate if vasodilation induced by the muscarinic receptor‐agonist methacholine (MCh) was owing to production of nitric oxide (NO). FMD during hyperaemia was assessed by ultrasound and FBF was measured by venous occlusion plethysmography during local infusion of MCh or L‐arginine in the human forearm. Both these methods were applied in 26 individuals. In another 12 individuals forearm arterial and venous plasma concentrations of nitrate/nitrite (NOx) were measured together with FBF before and during local MCh infusion.While the change in brachial artery diameter induced by sublingually given nitroglycerine and the vasodilatory response to sodium nitroprusside (SNP) given locally in the forearm were significantly correlated (r=0·70, P<0·01), FMD showed no relationship with the vasodilation evoked by MCh (r=–0·03) or
L‐arginine (r=0·04). The five‐fold increase in FBF during MCh infusion was associated with a significant increase in venous plasma NOx concentrations (P<0·05) and a more than 11‐fold increase in forearm NOx‐release (P<0·01). Thus, a significant relationship between the two methods regarding the evaluation of endothelium‐independent vasodilation evoked by NO‐donors was found, but no relationship was found between the two methods regarding the evaluation of endothelium‐dependent vasodilation. Furthermore, vasodilation induced by MCh in the forearm seems to be induced by NO‐release.
Mental stress increases right heart afterload in severe pulmonary hypertension
Authors: Schächinger Hartmut , Grob Michael , Ritz Rudolf , Solér Markus
Published: March 2003

Little is known about mental stress effects on the pulmonary circulation in health and disease. The current study was conducted to investigate whether pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) would further increase during standardized mental stress testing in patients with severe pulmonary hypertension. The study was a prospective analysis of seven patients (average age: 40 years, range from 21 to 56 years) with severe pulmonary hypertension (primary: n=4, secondary forms: n=3; resting mean pulmonary artery pressure ranged between 48 and 65 mmHg). Right heart catheterization for the determination of PAP, pulmonary capillary wedge pressure (PCW) and cardiac output (CO) was clinically indicated (diagnostic work‐up, acute drug testing). Patients accomplished a standardized 10 min mental stress test (computer based, adaptive complex reaction‐time task). Pulmonary haemodynamics during stress were compared to resting baseline. During mental stress mean PAP (±SEM) increased by 9·4 ± 2·1 mmHg (P<0·005). Pulmonary vascular resistance increased by 149 ± 25 dyne s cm–5 (P<0·001). Stroke volume decreased by 6·6 ± 2·2 ml (P<0·03). The data show that moderate mental stress increases right heart afterload in patients with severe pulmonary hypertension owing to elevation of PVR.
Cytological changes of the respiratory tract in young adults related to high levels of air pollution exposure
Authors: DJURIČIĆ  , PLAMENAC
Published: March 2003

djuričić s. and plamenac p. (1998) Cytopathology 9, 23–28

Cytological changes of the respiratory tract in young adults related to high levels of air pollution exposure

Several histopathological and cytological studies have shown that lesions of the respiratory tract epithelium become increasingly severe with duration of exposure to high levels of urban air pollution as well as with ageing of studied population groups. In this study we investigated and compared findings of cytological abnormalities in sputa of young adults (21–25 years of age) exposed to high levels of air pollution since birth with those who were exposed in the last 2–3 years only. All subjects were non‐smokers and were clinically healthy at the time of sampling. No significant differences in the incidence or severity of any of the cytological findings were found. The fact that even 10 times longer exposure to air pollution resulted in no major respiratory tract epithelial changes is, in our opinion, a result of the extremely efficient defence mechanisms and enormous regenerative potential of the respiratory tract of younger people.