bluuebunny/crossref_metadata_2025 huggingface dataset:
Caffeine ingestion does not impede the resynthesis of proglycogen and macroglycogen after prolonged exercise and carbohydrate supplementation in humans
Authors: Battram D. S. , Shearer J. , Robinson D. , Graham T. E.
Published: February 2004

The purpose of this study was to examine the effects of caffeine (Caf) ingestion on pro- (PG) and macroglycogen (MG) resynthesis in 10 healthy men. Subjects completed two trials, consisting of a glycogen-depleting exercise, while ingesting either Caf or placebo capsules. Throughout recovery, biopsies were taken at 0 (exhaustion), 30, 120, and 300 min, and 75 g of carbohydrate were ingested at 0, 60, 120, 180, and 240 min. Whereas Caf ingestion resulted in a higher blood glucose concentration and decreased glycogen synthase fractional velocity ( P ≤ 0.05), no effect was observed in either the amount or rate of PG and MG resynthesis. PG concentration increased significantly at each time point during recovery, whereas MG concentration remained unchanged until 120 min. The net rate of PG resynthesis was 115 mmol·kg dw-1·h-1 during the first 30 min of recovery, and then it significantly decreased by 62% throughout the remaining 4.5 h of recovery. The net rate of MG resynthesis was 77% lower than the net rate of PG resynthesis during the first 30 min of recovery and remained constant throughout 5 h of recovery despite increasing levels of insulin. In conclusion, Caf ingestion does not impede the resynthesis of PG or MG after an extensive depletion of muscle glycogen and with the provision of exogenous dietary carbohydrate.
Cardiovascular response to arousal from sleep under controlled conditions of central and peripheral chemoreceptor stimulation in humans
Authors: O'Driscoll Denise M. , Meadows Guy E. , Corfield Douglas R. , Simonds Anita K. , Morrell Mary J.
Published: February 2004

The cardiovascular response to an arousal occurring at the termination of an obstructive apnea is almost double that to a spontaneous arousal. We investigated the hypothesis that central plus peripheral chemoreceptor stimulation, induced by hypercapnic hypoxia (HH), augments the cardiovascular response to arousal from sleep. Auditory-induced arousals during normoxia and HH (>10-s duration) were analyzed in 13 healthy men [age 24 ± 1 (SE) yr]. Subjects breathed on a respiratory circuit that held arterial blood gases constant, despite the increased ventilation associated with arousal. Arousals were associated with a significant increase in mean arterial blood pressure at 5 s ( P < 0.001) and with a significant decrease in the R-R interval at 3 s ( P < 0.001); however, the magnitude of the changes was not significantly different during normoxia compared with HH (mean arterial blood pressure: normoxia, 91 ± 4 to 106 ± 4 mmHg; HH, 91 ± 4 to 109 ± 5 mmHg; P = 0.32; R-R interval: normoxia, 1.12 ± 0.04 to 1.02 ± 0.05 s; HH, 1.09 ± 0.05 to 0.92 ± 0.04 s; P = 0.78). Mean ventilation increased significantly at the second breath postarousal for both conditions ( P < 0.001), but the increase was not significantly different between the two conditions (normoxia, 5.35 ± 0.40 to 9.57 ± 1.69 l/min; HH, 8.57 ± 0.63 to 11.98 ± 0.70 l/min; P = 0.71). We conclude that combined central and peripheral chemoreceptor stimulation with the use of HH does not interact with the autonomic outflow associated with arousal from sleep to augment the cardiovascular response.
Exercise preserves endothelium-dependent relaxation in coronary arteries of hypercholesterolemic male pigs
Authors: Thompson Mark A. , Henderson Kyle K. , Woodman Christopher R. , Turk James R. , Rush James W. E. , Price Elmer , Laughlin M. Harold
Published: February 2004

We tested the hypothesis that exercise training (Ex) attenuates hypercholesterolemia-induced impairment of endothelium-dependent relaxation (EDR) in male porcine coronary arteries [left anterior descending coronary arteries (LAD)] by increasing nitric oxide (NO) release [due to increased endothelial NO synthase (NOS) expression] and/or increased bioactivity of NO. Adult male pigs were fed a normal-fat (NF) or high-fat (HF) diet for 20–24 wk. Pigs were Ex or remained sedentary (Sed) for 16–20 wk, beginning after 4 wk on diet. Four groups of pigs were used: NF-Sed, NF-Ex, HF-Sed, and HF-Ex. HF enhanced LAD contractions induced by KCl, aggregating platelets (AP), and serotonin (5-HT). AP and 5-HT produced EDR after blockade of cyclooxygenase with indomethacin (Indo) and smooth-muscle 5-HT2 receptors with ketanserin. HF impaired EDR induced by AP, 5-HT, and bradykinin. Results indicate a decreased contribution of NO to EDR in HF-Sed LADs, because the percentage of bradykinin-induced EDR inhibited by NG-nitro-l-arginine methyl ester was 27% in NF-Sed and 34% in NF-Ex but only 17% in HF-Sed. Also, NG-nitro-l-arginine methyl ester + Indo results indicate that release of an Indo-sensitive vasoconstrictor contributes to blunted EDR in HF-Sed LAD. Immunoblot and immunohistochemistry results indicate the following: 1) LAD endothelial NOS protein content was similar among groups; 2) HF decreased LAD superoxide dismutase (SOD) but increased caveolin-1 content; and 3) Ex increased SOD content of HF LADs. We conclude that HF impairs EDR by impairing the contribution of NO released from NOS (due to decreased SOD and increased caveolin-1 protein content) and by production of an Indo-sensitive vasoconstrictor. Ex preserves EDR in HF LADs by decreasing the production of the constrictor and increasing NO-release by NOS and/or NO bioactivity and bioavailability.
O2-regulated gene expression: transcriptional control of cardiorespiratory physiology by HIF-1
Authors: Semenza Gregg L.
Published: February 2004

The cardiovascular and respiratory systems play key roles in O2 homeostasis. Physiological responses to hypoxia involve changes in gene expression that are mediated by the transcriptional activator hypoxia-inducible factor (HIF)-1. Analysis of mice heterozygous for a knockout allele at the locus encoding the O2-regulated HIF-1α or HIF-2α subunit has revealed that these proteins are required for multiple physiological responses to chronic hypoxia, including erythrocytosis and pulmonary vascular remodeling. In mice with partial HIF-2α deficiency, hypoxia-induced expression of endothelin-1 and norepinephrine is dramatically impaired, and the mice fail to develop pulmonary hypertension after 4 wk of exposure to 10% O2. In mice with partial HIF-1α deficiency, the ability of the carotid body to sense and/or respond to acute or chronic hypoxia is lost. In wild-type mice, brief episodes of intermittent hypoxia are sufficient to induce production of erythropoietin (EPO), which protects the heart against apoptosis after ischemia-reperfusion, whereas in mice with partial HIF-1α deficiency, intermittent hypoxia does not induce EPO production or cardiac protection. Parenteral administration of EPO to rodents is sufficient to induce dramatic protection against ischemia-reperfusion injury in the heart. Thus HIF-1 mediates critical physiological responses to hypoxia, and the elucidation of these homeostatic mechanisms may lead to novel therapies for the most common causes of mortality in the US population.
V̇o2, V̇co2, and RQ in a respiratory chamber: accurate estimation based on a new mathematical model using the Kalman-Bucy method
Authors: Granato L. , Brandes A. , Bruni C. , Greco A. V. , Mingrone G.
Published: February 2004

A respiratory chamber is used for monitoring O2 consumption (V̇o2), CO2 production (V̇co2), and respiratory quotient (RQ) in humans, enabling long term (24-h) observation under free-living conditions. Computation of V̇o2 and V̇co2 is currently done by inversion of a mass balance equation, with no consideration of measurement errors and other uncertainties. To improve the accuracy of the results, a new mathematical model is suggested in the present study explicitly accounting for the presence of such uncertainties and error sources and enabling the use of optimal filtering methods. Experiments have been realized, injecting known gas quantities and estimating them using the proposed mathematical model and the Kalman-Bucy (KB) estimation method. The estimates obtained reproduce the known production rates much better than standard methods; in particular, the mean error when fitting the known production rates is 15.6 ± 0.9 vs. 186 ± 36 ml/min obtained using a conventional method. Experiments with 11 humans were carried out as well, where V̇o2 and V̇co2 were estimated. The variance of the estimation errors, produced by the KB method, appears relatively small and rapidly convergent. Spectral analysis is performed to assess the residual noise content in the estimates, revealing large improvement: 2.9 ± 0.8 vs. 3,440 ± 824 (ml/min)2 and 1.8 ± 0.5 vs. 2,057 ± 532 (ml/min)2, respectively, for V̇o2 and V̇co2 estimates. Consequently, the accuracy of the computed RQ is also highly improved (0.3 × 10-4 vs. 800 × 10-4). The presented study demonstrates the validity of the proposed model and the improvement in the results when using a KB estimation method to resolve it.
Cerebrovascular inflammation after brief episodic hypoxia: modulation by neuronal and endothelial nitric oxide synthase
Authors: Altay Tamer , Gonzales Ernesto R. , Park T. S. , Gidday Jeffrey M.
Published: February 2004

Obstructive sleep apnea, apnea of prematurity, and sudden infant death syndrome are associated with a high risk of morbidity and mortality secondary to the neuronal and cerebrovascular consequences of the associated intermittent hypoxia. We hypothesized that episodic hypoxia (EH) promotes inflammation in the cerebral microcirculation and that nitric oxide (NO) produced by the endothelial and neuronal isoforms of NO synthase (eNOS and nNOS, respectively) modulates this response. Anesthetized and ventilated Swiss-Webster ND4 mice, wild-type mice, and NO synthase knockout mice were subjected to a 1-h period of EH (twelve 30-s periods of hypoxia every 5 min). Four, 24, or 48 h later, mice were reanesthetized for imaging of leukocyte dynamics in the cortical venular microcirculation by epifluorescence videomicroscopy through closed cranial windows. In Swiss-Webster ND4 mice, leukocyte adherence increased 2.1-fold at 4 h, 3.4-fold at 24 h, and 1.8-fold at 48 h relative to time-matched, normoxic controls; there was no evidence of delayed hippocampal CA1 pyramidal cell death. A similar response was noted in wild-type mice. However, in eNOS knockouts, leukocyte-endothelial cell adherence was elevated to 4.4-fold over baseline 24 h after EH, and a significant fraction of these animals showed evidence of delayed CA1 cell death. Conversely, in nNOS knockouts, no increase in adherence was noted at 24 h and CA1 viability remained unaffected. We conclude that NO derived from nNOS promotes an inflammatory response in the cerebrovascular microcirculation after short-term EH and that NO produced by eNOS blunts the extent of this response and exerts neuroprotective effects.
Treatment with oxandrolone and the durability of effects in older men
Authors: Schroeder E. Todd , Zheng Ling , Yarasheski Kevin E. , Qian Dajun , Stewart Yolanda , Flores Carla , Martinez Carmen , Terk Michael , Sattler Fred R.
Published: February 2004

We investigated the effects of the anabolic androgen, oxandrolone, on lean body mass (LBM), muscle size, fat, and maximum voluntary muscle strength, and we determined the durability of effects after treatment was stopped. Thirty-two healthy 60- to 87-yr-old men were randomized to receive 20 mg oxandrolone/day ( n = 20) or placebo ( n = 12) for 12 wk. Body composition [dual-energy X-ray absorptiometry (DEXA), magnetic resonance imaging, and 2H2O dilution] and muscle strength [1 repetition maximum (1 RM)] were evaluated at baseline and after 12 wk of treatment; body composition (DEXA) and 1-RM strength were then assessed 12 wk after treatment was discontinued ( week 24). At week 12, oxandrolone increased LBM by 3.0 ± 1.5 kg ( P < 0.001), total body water by 2.9 ± 3.7 kg ( P = 0.002), and proximal thigh muscle area by 12.4 ± 8.4 cm2 ( P < 0.001); these increases were greater ( P < 0.003) than in the placebo group. Oxandrolone increased 1-RM strength for leg press by 6.7 ± 6.4% ( P < 0.001), leg flexion by 7.0 ± 7.8% ( P < 0.001), chest press by 9.3 ± 6.7% ( P < 0.001), and latissimus pull-down exercises by 5.1 ± 9.1% ( P = 0.02); these increases were greater than placebo. Oxandrolone reduced total (-1.9 ± 1.0 kg) and trunk fat (-1.3 ± 0.6 kg; P < 0.001), and these decreases were greater ( P < 0.001) than placebo. Twelve weeks after oxandrolone was discontinued ( week 24), the increments in LBM and muscle strength were no longer different from baseline ( P > 0.15). However, the decreases in total and trunk fat were sustained (-1.5 ± 1.8, P = 0.001 and -1.0 ± 1.1 kg, P < 0.001, respectively). Thus oxandrolone induced short-term improvements in LBM, muscle area, and strength, while reducing whole body and trunk adiposity. Anabolic improvements were lost 12 wk after discontinuing oxandrolone, whereas improvements in fat mass were largely sustained.
Analysis of expression and posttranslational modification of proteins during hypoxia
Authors: Kumar Ganesh K. , Klein Jon B.
Published: February 2004

The cellular responses to hypoxia are complex and characterized by alterations in the expression of a number of genes, including stress-related genes and corresponding proteins that are necessary to maintain homeostasis. The purpose of this article is to review previous and recent studies that have examined the changes in the expression and posttranslational modification of proteins in response to chronic sustained and intermittent forms of hypoxia. A large number of studies focused on the analysis of either the single protein or a subset of related proteins using one-dimensional gel electrophoresis to separate a complex set of proteins from solubilized tissues or cell extracts, followed by immunostaining of proteins using antibodies that are specific to either native or posttranslationally modified forms. On the other hand, only a limited number of studies have examined the global perturbations on protein expression by hypoxia using proteomics approach involving two-dimensional electrophoresis coupled with mass spectrometry. Results derived from specific protein analysis of a variety of tissues and cells showed that hypoxia, depending on the duration and severity of the stimulus, affects the level and the state of posttranslational modification of a subset of proteins that are associated with energy metabolism, stress response, cell injury, development, and apoptosis. Some of these earlier findings are further corroborated by recent studies that utilize a global proteomics approach, and, more importantly, results from these proteomics investigations on the effects of hypoxia provide new protein targets for further functional analysis. The anticipated new information stems from the analysis of expression, and posttranslational modification of these novel protein targets, along with gene expression profiles, offers exciting new opportunities to further define the mechanisms of cellular responses to hypoxia and to control more effectively the clinical consequences of prolonged or periodic lack of oxygen.
Facilitation of dopamine and acetylcholine release by intermittent hypoxia in PC12 cells: involvement of calcium and reactive oxygen species
Authors: Kim Dong-Kyu , Natarajan Niranjana , Prabhakar Nanduri R. , Kumar Ganesh K.
Published: February 2004

We have investigated the effects of preconditioning pheochromocytoma (PC12) cells with intermittent hypoxia (IH) on transmitter release during acute hypoxia. Cell cultures were exposed to either alternating cycles of hypoxia (1% O2+ 5% CO2; 30 s/cycle) and normoxia (21% O2+ 5% CO2; 3 min/cycle) for 15 or 60 cycles or normoxia alone (control) for similar durations. Control and IH cells were challenged with either hyperoxia (basal release) or acute hypoxia (Po2of ∼35 Torr) for 5 min, and the amounts of dopamine (DA) and acetylcholine (ACh) released in the medium were determined by HPLC combined with electrochemical detection. Hypoxia augmented DA (∼80%) but not ACh release in naive cells, whereas, in IH-conditioned cells, it further enhanced DA release (ranging from 120 to ∼145%) and facilitated ACh release (∼30%). Hypoxia-evoked augmentation of transmitter release was not seen in cells conditioned with sustained hypoxia. IH-induced increase in DA but not IH-induced ACh release during hypoxia was partially inhibited by cadmium chloride (100 μM), a voltage-gated Ca2+channel blocker. By contrast, 2-aminoethoxydiphenylborate (75 μM), a blocker of inositol 1,4,5-trisphosphate (IP3) receptors, and N-acetyl-l-cysteine (300 μM), a potent scavenger of reactive oxygen species, either attenuated or abolished IH-evoked augmentation of transmitter release during hypoxia. Together, the above results demonstrate that IH conditioning increases hypoxia-evoked neurotransmitter release from PC12 cells via mechanisms involving mobilization of Ca2+from intracellular stores through activation of IP3receptors. Our findings also suggest that oxidative stress plays a central role in IH-induced augmentation of transmitter release from PC12 cells during acute hypoxia.
Evaluation of bioimpedance spectroscopy for measurements of body water distribution in healthy women before, during, and after pregnancy
Authors: Lof Marie , Forsum Elisabet
Published: February 2004

Bioimpedance spectroscopy (BIS) is a technique of interest in the study of human pregnancy because it can assess extracellular (ECW), intracellular (ICW), and total body water (TBW) as ECW plus ICW. The technique requires appropriate resistivity coefficients and has not been sufficiently evaluated during the reproductive cycle. Therefore, in a methodological study, we estimated ECW, ICW, and TBW, by means of BIS, and compared the results with the corresponding estimates obtained by using reference methods. Furthermore, results obtained by means of population-specific resistivity coefficients were compared with results obtained by means of general resistivity coefficients. These comparisons were made before pregnancy, in gestational weeks 14 and 32, as well as 2 wk postpartum in 21 healthy women. The reference methods were isotope and bromide dilution. Average ICW, ECW, and TBW, estimated by means of BIS, were in agreement with reference data before pregnancy, in gestational week 14, and postpartum. The corresponding comparison in gestational week 32 showed good agreement for ICW, whereas estimates by means of BIS were significantly ( P < 0.001) lower than the corresponding reference values for ECW and TBW. Thus the BIS technique, which was based on a model developed for the nonpregnant body, estimated increases in ICW accurately, whereas increases in ECW and TBW tended to be underestimated. Estimates obtained by using population-specific and general resistivity coefficients were very similar. In conclusion, the results indicated that BIS is potentially useful for studies during pregnancy but that further work is needed before it can be generally applied in such studies.
Impact of interrupted leptin pathways on ventilatory control
Authors: Polotsky Vsevolod Y. , Smaldone Marc C. , Scharf Matthew T. , Li Jianguo , Tankersley Clarke G. , Smith Philip L. , Schwartz Alan R. , O'Donnell Christopher P.
Published: February 2004

Leptin deficiency in ob/ob mice produces marked depression of the hypercapnic ventilatory response, particularly during sleep. We now extend our previous findings to determine whether 1) leptin deficiency affects the hypoxic ventilatory response and 2) blockade of the downstream excitatory actions of leptin on melanocortin 4 receptors or inhibitory actions on neuropeptide Y (NPY) pathways has an impact on hypercapnic and hypoxic sensitivity. We have found that leptin-deficient ob/ob mice have the same hypoxic ventilatory response as weight-matched wild-type obese mice. There were no differences in the hypoxic sensitivity between agouti yellow mice and weight-matched controls, or NPY-deficient mice and wild-type littermates. Agouti yellow mice, with blocked melanocortin pathways, exhibited a significant depression of the hypercapnic sensitivity compared with weight-matched wild-type controls during non-rapid eye movement sleep (5.8 ± 0.7 vs. 8.9 ± 0.7 ml·min-1·%CO2-1, P < 0.01), but not during wakefulness. NPY-deficient transgenic mice exhibited a small increase in the hypercapnic ventilatory response compared with wild-type littermates, but this was only present during wakefulness. We conclude that interruption of leptin pathways does not affect hypoxic sensitivity during sleep and wakefulness but that melanocortin 4 blockade is associated with depressed hypercapnic sensitivity in non-rapid eye movement sleep.
Modeling pulmonary nitric oxide exchange
Authors: George Steven C. , Hogman Marieann , Permutt Solbert , Silkoff Philip E.
Published: February 2004

Nitric oxide (NO) was first detected in the exhaled breath more than a decade ago and has since been investigated as a noninvasive means of assessing lung inflammation. Exhaled NO arises from the airway and alveolar compartments, and new analytical methods have been developed to characterize these sources. A simple two-compartment model can adequately represent many of the observed experimental observations of exhaled concentration, including the marked dependence on exhalation flow rate. The model characterizes NO exchange by using three flow-independent exchange parameters. Two of the parameters describe the airway compartment (airway NO diffusing capacity and either the maximum airway wall NO flux or the airway wall NO concentration), and the third parameter describes the alveolar region (steady-state alveolar NO concentration). A potential advantage of the two-compartment model is the ability to partition exhaled NO into an airway and alveolar source and thus improve the specificity of detecting altered NO exchange dynamics that differentially impact these regions of the lungs. Several analytical techniques have been developed to estimate the flow-independent parameters in both health and disease. Future studies will focus on improving our fundamental understanding of NO exchange dynamics, the analytical techniques used to characterize NO exchange dynamics, as well as the physiological interpretation and the clinical relevance of the flow-independent parameters.
Influence of Contrast on Orientation and Temporal Frequency Tuning in Ferret Primary Visual Cortex
Authors: Alitto Henry J. , Usrey W. Martin
Published: February 2004

Neurons in primary visual cortex are highly sensitive to the contrast, orientation, and temporal frequency of a visual stimulus. These three stimulus properties can be varied independently of one another, raising the question of how they interact to influence neuronal responses. We recorded from individual neurons in ferret primary visual cortex to determine the influence of stimulus contrast on orientation tuning, temporal-frequency tuning, and latency to visual response. Results show that orientation-tuning bandwidth is not affected by contrast level. Thus neurons in ferret visual cortex display contrast-invariant orientation tuning. Stimulus contrast does, however, influence the structure of orientation-tuning curves as measures of circular variance vary inversely with contrast for both simple and complex cells. This change in circular variance depends, in part, on a contrast-dependent change in the ratio of null to preferred orientation responses. Stimulus contrast also has an influence on the temporal-frequency tuning of cortical neurons. Both simple and complex cells display a contrast-dependent rightward shift in their temporal frequency-tuning curves that results in an increase in the highest temporal frequency needed to produce a half-maximum response (TF50). Results show that the degree of the contrast-dependent increase in TF50 is similar for cortical neurons and neurons in the lateral geniculate nucleus (LGN) and indicate that subcortical mechanisms likely play a major role in establishing the degree of effect displayed by downstream neurons. Finally, results show that LGN and cortical neurons experience a contrast-dependent phase advance in their visual response. This phase advance is most pronounced for cortical neurons indicating a role for both subcortical and cortical mechanisms.
Reorganization of Reflex Responses Mediated by Different Afferent Sensory Fibers After Spinal Cord Transection
Authors: Valero-Cabré Antoni , Forés Joaquim , Navarro Xavier
Published: February 2004

Adult rats were submitted to a complete spinal cord transection at T9 level to address peripheral and spinal reflex changes in the caudal lumbar segments. Compound muscle and nerve action potentials decreased in amplitude and increased their duration between 14 and 30 days but recovered to near to normal values thereafter. The H wave amplitude increased during follow-up, resulting in significantly higher H/M ratio in tibialis anterior (223%), gastrocnemius (160%), and plantar (304%) muscles with respect to preoperatory values ( P < 0.01). Sixty minutes after spinal cord transection, component C1 (conveyed by Aαβ afferents) disappeared in the crossed but not in the ipsilateral withdrawal reflex. Components C2 (Aδ) and C3 (C afferents) were abolished on both. C1 and C3 reappeared for both reflexes in all injured animals, while C2 reappeared in a few cases. C1 ipsilateral component became highly facilitated (209% of presurgery values, P < 0.01), whereas C3 (82%) and C2 (24%) recovered partially. Crossed reflex component C1 attained in all animals similar to normal values (85%) but with longer duration. C3 increased with time although it remained significantly lower than the original (67%) whereas C2 reappeared in only 2/8 animals. In conclusion, spinal cord injury induces a transient disability of caudal spinal cord segments that progressively reverts along time. Ipsilateral reflex components mediated by thick Aαβ fibers (H reflex and C1) but not those mediated by thin fibers (C2 and C3) remained present after injury showing long-lasting facilitation whereas contralateral reflex components were abolished after injury and showed limited recovery.
Stem Cell Transplantation and Ethics: A European Overview
Authors: Holm Søren
Published: February 2004

Stem cell transplantation requires a source of stem cells. The potential use of human embryonic stem cells for research and therapy has created major ethical and political debates in Europe. The first section of this paper gives an overview of the official regulatory responses to the possibility of stem cell transplantation in a range of European jurisdictions. It focuses on the regulation of: (1) the use and production of embryonic stem cells, (2) the use of adult stem cells, and (3) the patenting of stem cell lines and products. The second section tries to unravel why regulatory responses have differed between different European countries, especially with regard to embryonic stem cells and focuses on two possible explanations for the differences: (1) ethical disagreement and (2) maintenance of regulatory consistency. It is argued that an exclusive focus on ethical disagreement cannot fully explain the differences in regulatory response, and that an understanding of the specific way in which regulations develop over time in each jurisdiction is crucial. Certain types of ethical consistency arguments can, for instance, only be mounted successfully if the jurisdiction in question already allows other forms of experiments involving human embryos. In the final section it is argued that the European regulatory developments in the future may be crucially dependent on whether actual stem cell products are developed that can potentially be traded across borders.
Genetic Amniocentesis in Multiple Pregnancy
Authors: Tóth-Pál Ernő , Papp Csaba , Beke Artúr , Bán Zoltán , Papp Zoltán
Published: February 2004

Objectives: Second-trimester genetic amniocentesis is the most frequently used invasive prenatal diagnostic technique. Several reports have been published about the effect of genetic amniocentesis on fetal loss in multiple pregnancies over the past two decades. Here we analyze our experience with genetic amniocentesis in multiple pregnancies over the past 10 years. Methods: Details of 184 multiple pregnancies were processed in all cases in whom genetic amniocentesis was performed in women who presented at our department since 1990. The outcomes of 175 cases (95.1%) out of 184 genetic amniocenteses were available to us. As a control group, we followed up the outcome of 300 twin pregnancies in which no genetic amniocenteses were performed. Results: We found that the proportion of spontaneous losses in multiple pregnancies between the 18th and the 24th gestational weeks was 2.39%, whereas if genetic amniocentesis was performed the loss rate before the 24th week was 3.87%. The perinatal mortality rate was 10.03/1,000 in the group who underwent amniocentesis, while it was 10.52/1,000 in the group without amniocentesis. Conclusions: Our results suggest that the genetic amniocentesis performed in multiple pregnancies slightly increased (1.48%) the fetal loss rate until the 24th week. Beyond 5 weeks after the procedure, no consequent fetal loss should be expected. In our study the intervention did not have any undesired effect on perinatal mortality rates.
Effect of Smoking on Serum Concentrations of Total Homocysteine, Folate, Vitamin B12, and Nitric Oxide in Pregnancy: A Preliminary Study
Authors: Özerol Elif , Özerol Ibrahim , Gökdeniz Remzi , Temel Ismail , Akyol Omer
Published: February 2004

Objective: Nitric oxide (NO) is a potent vasodilator released by endothelial cells that plays an important role in modulating maternal and fetal vascular tone in normal pregnancy. Lower plasma levels of vitamins may result in hyperhomocysteinemia, a known risk factor in pregnancy. The aim of this study was to investigate whether there are alterations in the serum levels of total homocysteine (tHcy), folate, vitamin B12, and total nitrite, as an index of NO, in smoking as compared with age-matched nonsmoking pregnant women. Methods: Thirty-three women (19 smoking and 14 nonsmoking) between 16 and 22 weeks of their gestation were included in this study. The serum tHcy levels were analyzed by using an enzyme-linked immunosorbent assay kit. Vitamin B12 and folate values were measured by means of DPC kits. Total nitrite was measured by Griess reaction as an index of endogenous NO production. Results: The serum tHcy concentrations were significantly increased in smoking as compared with nonsmoking pregnant women (p < 0.001). The folate and vitamin B12 concentrations were lower in smoking than in nonsmoking pregnant women, but only the differences in folate concentrations were statistically significant (p < 0.001). The tHcy concentrations showed a significant negative correlation with folate in the smoking pregnant women. The serum total nitrite concentrations were lower in smoking than in nonsmoking pregnant women (p < 0.05). In addition, the serum nitrite levels in smoking pregnant women had significant negative correlations with tHcy and positive correlations with folate and vitamin B12 levels. Conclusions: In the light of our findings, we propose that smoking might enhance the vasoconstrictor capacity in pregnant women by increased tHcy concentrations and by a simultaneous decrease in the production of NO which is a vasodilator compound.
A Comparison between Maternal Serum Free β-Human Chorionic Gonadotrophin and Pregnancy-Associated Plasma Protein A Levels in First-Trimester Twin and Singleton Pregnancies
Authors: Mashiach Roy , Orr-Urtreger Avi , Yaron Yuval
Published: February 2004

Objectives: To determine the levels of first-trimester free β-human chorionic gonadotrophin (free βhCG), pregnancy-associated plasma protein A (PAPP-A) and nuchal translucency (NT) in twin pregnancies. Methods: The study included 93 patients with twin pregnancy and 4,977 with singletons who underwent first-trimester testing using free βhCG, PAPP-A and NT at 10–13 weeks of gestational age. Results: In twin pregnancies, the maternal serum free βhCG level was 2.18 higher and the PAPP-A level was 2.38 higher than in singleton pregnancies. These marker levels were significantly higher than the expected 2.0 multiples of the median (MoM). In contrast, NT values did not differ between twins and singletons. Conclusion: These data may be used to establish first-trimester combined screening for twin pregnancies.
Fetal Hemolytic Disease due to Anti-Rh17 Alloimmunization
Authors: Hirose Masaya , Nakanishi Keiko , Kaku Shouji , Moro Hiroko , Hodohara Keiko , Aotani Hirofumi , Takebayashi Koichi , Noda Yoichi
Published: February 2004

Objective: To delineate clinical features of a case of fetal hemolytic disease due to anti-Rh17, along with a review of relevant studies published in English and Japanese. Methods: We present clinical features of a –D-/-D- phenotype woman with anti-Rh17 alloimmunization during pregnancy. Relevant English literature in the MEDLINE database was reviewed, while Japanese studies were searched in the Japana Centra Revuo Medicina database. Results: A Japanese –D-/-D- woman with anti-Rh17 (Hro) was treated during pregnancy. Serial ultrasonography, antibody titers, amniocenteses, and cordocenteses were conducted for perinatal management. Amniocentesis results demonstrated a high delta optical density level of 450 in the amniotic fluid, while cordocentesis revealed alloimmunization between the mother and the fetus as well as fetal hemolytic anemia. Blood flow velocity in the middle cerebral artery indicated a rapid development of fetal anemia. The newborn demonstrated severe anemia and hyperbilirubinemia, which were successfully treated with exchange transfusions. Two cases of prenatally diagnosed fetal hemolytic disease due to anti-Rh17 were found published in English and 5 in Japanese. Conclusion: A –D-/-D- phenotype patient with anti-Rh17 was successfully managed during pregnancy and a good outcome for the neonate was achieved. Our results and a review of related literature led to the following suggestions. The first pregnancy in a –D-/-D- woman may be affected, an anamnestic immune response can easily occur during pregnancy, the level of anti-Rh17 titer is indicative of the degree of fetal hemolysis, and appropriate intrauterine intervention is warranted for achievement of a good outcome.
First-Trimester Findings Associated with Twin Reversed Arterial Perfusion Sequence
Authors: Kamitomo Masato , Kouno Satoshi , Ibuka Kyoko , Oku Shouzou , Sueyoshi Kazunobu , Maeda Takatsugu , Hatae Masayuki
Published: February 2004

Introduction: Regarding its pathogenesis, discordant development in early gestation, as well as vascular anastomoses between twins are postulated to be required for the establishment of the twin-reversed arterial perfusion (TRAP) sequence. However, first trimester findings associated with this complication have not yet been reported. Case: A discordant monochorionic twin was revealed upon examination of a 24-year-old primigravida at 11 weeks’ gestation. Cystic masses were identified on the back of the smaller twin, later followed by the appearance of skin edema and pericardial effusion, indicating cardiac failure. Subsequently, despite diagnosis of fetal demise at 15 weeks the lower body was shown to have further developed and the heartbeats appeared again, resulting in an acardia anceps or hemicardia. No remarkable change was observed in the larger normal twin. Conclusion: This occurrence was considered consistent with the current hypothesis regarding the pathogenesis of the acardiac anomaly. First trimester discordancy in a monochorionic twin gestation is considered to represent an early manifestation of TRAP sequence.
Neuroendocrine Aspects of Chronic Fatigue Syndrome
Authors: Papanicolaou Dimitris A. , Amsterdam Jay D. , Levine Susan , McCann Samuel M. , Moore Rebecca C. , Newbrand Clare H. , Allen Glen , Nisenbaum Rosane , Pfaff Donald W. , Tsokos George C. , Vgontzas Alexandros N. , Kales Anthony
Published: February 2004

Chronic fatigue syndrome (CFS) is a serious health concern affecting over 800,000 Americans of all ages, races, socioeconomic groups and genders. The etiology and pathophysiology of CFS are unknown, yet studies have suggested an involvement of the neuroendocrine system. A symposium was organized in March 2001 to explore the possibility of an association between neuroendocrine dysfunction and CFS, with special emphasis on the interactions between neuroendocrine dysfunction and other abnormalities noted in the immune and autonomic nervous systems of individuals with CFS. This paper represents the consensus of the panel of experts who participated in this meeting.
Regulation of Leukocyte Function-Associated Antigen 1-Mediated Adhesion by Somatostatin and Substance P in Mouse Spleen Cells
Authors: Kang Bit-Na , Kim Ho-Jun , Jeong Kyu-Shik , Park Sang-Joon , Kim Sung-Ho , Kim Se-Ra , Kim Tae-Hwan , Ryu Si-Yun
Published: February 2004

Background: Interaction of the integrin leukocyte function-associated antigen (LFA)-1 (CD11a/CD18) with its ligands, the intercellular adhesion molecules (ICAM)-1, -2, and -3 (CD54, CD102, and CD50), is pivotal to many leukocyte adhesion events. Method: To define the mechanism of the movement of leukocytes to the inflammatory site by somatostatin (SOM) and substance P (SP), we examined the expression of the adhesion molecule LFA-1 and inside-out signals for integrins, protein kinase C (PKC), Ras, Rap1, and phosphoinositide (PI) 3-kinase, in anti-CD3-, anti-CD3+SOM-, anti-CD3+SP-stimulated or unstimulated spleen cells. Results: SOM caused down-regulation of LFA-1 mRNA translation as well as of adhesion-stimulating molecules such as Rap1, Ras, and PI 3-kinase. On the other hand, SP slightly induced LFA-1 mRNA translation and activation signals for integrins. The early-phase alteration of LFA-1 mRNA translation after 3 h of culture may be due to the changes of CD8+ T cells rather than changes of CD4+ cells. In adhesion assays, SOM significantly decreased cell adhesion (p < 0.05). Conclusion: These data suggest that SOM treatment of spleen cells, especially in CD8+ T cells, leads to downregulation of LFA-1 mRNA translation, inside-out signaling molecules for integrins (Ras, Rap1 and PI 3-kinase, but not PKC), and consequently to a decrease in the LFA-1-mediated adhesion to ICAM-1.
The Effects of a Switch-Off Response Accompanied by Hypothalamically Induced Restlessness on Immunoendocrinological Changes in Cats
Authors: Sumida Yasuhisa , Kaname Hitoshi , Mori Yoshinobu , Kojima Kyoji , Kubo Chiharu , Tashiro Nobutada
Published: February 2004

Electrical stimulation of the anterior hypothalamus in cats elicits a behavior called restlessness. When a switch is available for the cats to shut off the electrical stimulation, the cats learn to turn off the stimulation (switch-off response; SOR). In this study, we examined the relationship between the SOR and immunoendocrinological alterations. First of all, an escapable stimulation, in which cats could turn off the stimulation, was applied (escapable condition; EC). One month later, inescapable stimulation was delivered under the same conditions except for the fact that the cats could not turn off the stimulation (inescapable condition; IC). A behavioral analysis revealed that unstable patterns of behavior and a reduction in motor activity were observed in IC compared with those in EC. Furthermore, no significant changes in peripheral leukocytes were observed, while plasma epinephrine and cortisol transiently increased after the series of stimulations, but immediately decreased after the end of the stimulation in EC. On the other hand, there was a greater and prolonged increase in the number of peripheral granulocytes and the plasma levels of epinephrine and cortisol from 1 to 2 h after the stimulation until the end of the experiment in IC. Regarding the number of peripheral lymphocytes, CD4+ or CD8+ lymphocytes and the CD4+ to CD8+ ratio, no significant differences were found between EC and IC. These results suggest that the inability to escape from the aversive stimulation caused a decrease in movement and a prolonged alteration of the immune and endocrine systems, as is often observed in learned helplessness.
Differential Effects of Light/Dark Recombinant Human Prolactin Administration on the Submaxillary Lymph Nodes and Spleen Activity of Adult Male Mice
Authors: Esquifino A.I. , Arce A. , Alvarez M.P. , Chacon F. , Brown-Borg H. , Bartke A.
Published: February 2004

Objectives: Day/night variations in cellularity, percentage of CD4+, CD8+ and double-positive (CD4+–CD8+) lymphocytes, lipopolysaccharide (LPS)- and concanavalin A (Con A)-induced lymphocyte proliferation and natural killer (NK) activity, and the effect of timed administration of recombinant human prolactin (h-PRL) on the above-mentioned parameters were investigated in the submaxillary lymph nodes and spleen of adult male mice. Results: In controls, the percentage of CD4+, double-positive lymphocytes, LPS- or Con A-induced blastogenic proliferation and NK activity in the spleen differ during the dark phase as compared to the light phase. When administered during the dark period, h-PRL induced immunosuppresion in the percentage of CD4+, double-positive (CD4+–CD8+) lymphocytes. Con A- and LPS-induced lymphocyte proliferation and NK activity as compared to untreated controls. When h-PRL was administered during the light period, the cellularity increased, and h-PRL was immunosuppressive in Con A- and LPS-induced lymphcoyte proliferation and NK activity as compared to controls. Moreover, in control submaxillary lymph nodes the cellularity, percentage of CD8+, double-positive lymphocytes, blastogenic proliferation in the presence of Con A and LPS and NK activity differ when comparing the dark with the light phase. When administered during the dark period h-PRL induced immunosuppression in the percentage of double-positive (CD4+–CD8+) lymphocytes, Con A- and LPS-induced lymphocyte proliferation as compared to controls. When h-PRL is administered during the light period, no effects were observed. Conclusions: These results indicate the existence of differential day/night variations in the cellular immune response depending upon the lymphoid organ considered. Because of the administration of h-PRL a differential modulation of this circadian variation was also observed.
IL-10 Inhibits Nitric Oxide Synthesis in Murine Uterus
Authors: Ogando Diego , Cella Maximiliano , Ribeiro María Laura , Weissmann Carina , Aisemberg Julieta , Franchi Ana
Published: February 2004

Objectives: Recent reports point to a role for the nitric oxide/nitric oxide synthase (NO/NOS) system in implantation. It has been suggested that inducible NOS expressed at peri-implantation would lead to enhanced NO production, which could promote the attachment of the blastocyst. Short-term administration of NO donors during the pre-implantation period reduced the pregnancy rate in a dose-dependent manner. Thus, it is thought that optimal levels of NO are critical for embryo implantation, so regulation of NOS must be crucial. Taking this into consideration, interleukin-10 (IL-10), synthesized and secreted by the embryo, could be modulating NOS during implantation. In this study we have investigated the in vitro effect of IL-10 on NOS in the uterus. Methods: To determine the effect of IL-10, slices of uterus from estrogenized mice were pre-incubated for 60 min with different concentrations of IL-10 and NOS activity was measured. Results: IL-10 (50 and 100 ng/ml in vitro) diminished NOS activity. The in vivo administration of lipopolysaccharide (LPS; 8 mg/kg) significantly increased the conversion of arginine into citrulline. This effect was abolished after 60 min of preincubation with IL-10 (100 ng/ml). The stimulatory effect of LPS and estrogen on NOS activity is exerted on the Ca-independent isoform and IL-10 in vitro abolished this increase. We observed that the uterus of pregnant mice on day 5 of gestation synthesized NO. This production was significantly inhibited by preincubation with IL-10 (100 ng/ml). Conclusions: This report demonstrates that IL-10 is capable of inhibiting NO synthesis in estrogenized, LPS-treated and pregnant rat uterus.
Inhibition of Ras-GTPase Improves Diabetes-Induced Abnormal Vascular Reactivity in the Rat Perfused Mesenteric Vascular Bed
Authors: Yousif Mariam H.M. , Benter Ibrahim F. , Abraham Saju , Akhtar Saghir
Published: February 2004

Objective: The signalling mechanisms involved in regulating altered vascular reactivity in diabetes are not fully understood. The aim of this study was to investigate the role of Ras-GTPase in the development of abnormal vascular reactivity in diabetes. Materials and Methods: We investigated the ability of chronic administration of FPTIII (1.5 mg/kg), an inhibitor of Ras-GTPase, to modulate the altered vasoreactivity of the rat perfused mesenteric bed to common vasoconstrictors and vasodilators in streptozotocin (STZ)-induced diabetes. Results: The vasoconstrictor responses induced by norepinephrine (NE) and endothelin-1 (ET-1) were significantly increased whereas vasodilator responses to carbachol, histamine and isoprenaline were significantly reduced in the perfused mesenteric bed of the STZ-diabetic rats. Inhibition of Ras-GTPase by chronic administration of FPTIII produced a significant normalization of the altered agonist-induced vasoconstrictor and vasodilator responses without affecting blood glucose levels. Inhibition of Ras-GTPase did not affect the agonist-induced vasoconstrictor and vasodilator responses in the control animals. Conclusion: These data suggest that signal transduction pathways activated by Ras-GTPase are involved in the development of diabetic vascular dysfunction. Potential strategies aimed at modifying actions of signal transduction pathways involving Ras-GTPase may therefore prove to be beneficial in treatment of vascular complications in diabetes.
Differential Distribution of Risk Factors and Outcome of Acute Coronary Syndrome in Kuwait: Three Years’ Experience
Authors: Zubaid M. , Suresh C.G. , Thalib L. , Rashed W.
Published: February 2004

Objective: To compare the distribution of risk factors and clinical outcome of acute coronary syndrome (ACS) between Kuwaiti and other Arab men living in Kuwait. Subjects and Methods: The data for this study was collected from the computerized database at the Mubarak Al-Kabeer Hospital, Kuwait and the 1997–2000 census data for the State of Kuwait. 1,329 Arab men (666 Kuwaitis and 663 other Arabs) older than 25 years who were admitted between September 1997 and August 2000 with a diagnosis of ACS were included in the study. Results: The rate of admission for the entire patient population was twofold higher for Kuwaiti (1.68/1,000) than other Arab men (0.72/1,000), (p < 0.001); the mean age of the Kuwaiti men was 56.7 ± 11.9 years and other Arab men 53.0 ± 10.5 years (p < 0.001). The prevalence of hypertension, diabetes, smoking and hypercholesterolemia for Kuwaiti men was 35.9, 56.9, 51.7 and 36.2%, respectively; the corresponding prevalence for other Arab men was 28.8, 42.7, 68.2 and 32.0%, the difference in the prevalence except for hypercholesterolemia was significant (p < 0.001). In Kuwaiti men younger than 55 years of age, the prevalence of hypertension, diabetes mellitus, smoking and hypercholesterolemia was 26.6, 49.5, 68.6 and 43.3%, respectively; the corresponding values for other Arab men was 22.3, 36.2, 77.7 and 43.3%; the difference in prevalence except for hypertension was significant (p < 0.001). The in-hospital mortality for the whole study was 6.2% (Kuwaiti) and 2.3% (other Arab men; p < 0.001); while that for men younger than 55 years was 2.7% (Kuwaiti) and 0.8% (other Arab men; p < 0.05). Conclusion: The rate of admission for the entire patient population with a diagnosis of ACS was twofold higher for Kuwaiti than other Arab men. Among all patients and also those less than 55 years, the prevalence of diabetes mellitus was consistently higher among Kuwaiti than other Arab men thereby probably leading to the higher admission rate and in-hospital mortality.