The relationship between sperm velocity and individual age, size, body condition and fluctuating asymmetry was investigated in Alpine whitefish Coregonus fatioi. The fish analysed belonged to one ...among several sympatric whitefish populations of Lake Thun, Switzerland, which are characterized by a high prevalence of gonad alterations. Therefore, sperm velocity data were also tested for a link between gonad deformation and sperm swimming speed. Sperm velocity was significantly lower in larger‐grown individuals and in individuals of higher body condition. As expected, sperm velocity was higher in males with higher levels of fluctuating asymmetry, but it did not significantly vary with male age. Moreover, variation in sperm velocity was found to be significantly higher in individuals showing some types of gonad alterations but it did not significantly correlate with the presence of other types of alterations.
Small or decreasing populations call for emergency actions like, for example, captive breeding programs. Such programs aim at rapidly increasing population sizes in order to reduce the loss of ...genetic variability and to avoid possible Allee effects. The Lesser Kestrel Falco naumanni is one of the species that is currently supported in several captive breeding programs at various locations. Here, we model the demographic and genetic consequences of potential management strategies that are based on offspring sex ratio manipulation. Increased population growth could be achieved by manipulating female conditions and/or male attractiveness in the captive breeders and consequently shifting the offspring sex ratio towards more female offspring, which are then used for reintroduction. Fragmenting populations into wild‐breeding and captive‐breeding demes and manipulating population sex ratio both immediately increase the inbreeding coefficient in the next generation (i.e. decrease Ne) but may, in the long term, reduce the loss of genetic variability if population growth is restricted by the number of females. We use the Lesser Kestrel and the wealth of information that is available on this species to predict the long‐term consequences of various kinds of sex‐ratio manipulation. We find that, in our example and possibly in many other cases, a sex‐ratio manipulation that seems realistic could have a beneficial effect on the captive breeding program. However, the possible long‐term costs and benefits of such measures need to be carefully optimized.
Abstract
Introduction:
In mammals, there is evidence that glutamate has a role as a wake-active neurotransmitter. So using video-based analysis of Drosophila behavior, we undertook a study to examine ...if glutamate, which has been previously shown to have an excitatory role in neuromuscular junctions in Drosophila, may have a conserved wake-active role in the adult brain.
Aims and Methods:
Using 6- to 9-day-old female flies, we examined the effect of perturbations of the glutamatergic signaling on total wakefulness and wake bout architecture. We increased and decreased neuronal activity of glutamatergic neurons in the brains of adult flies using Upstream Activating Sequence (UAS) NaChBac and UAS EKO, respectively. We blocked neurotransmission from glutamatergic neurons in adult flies using the UAS-driven temperature-sensitive dynamin mutation shibirets. We examined the behavior of flies with loss of function mutations of individual subunits of brain-specific ionotropic glutamate receptors.
Results:
Increasing the activity of glutamatergic neurons in the adult brain led to a significant increase in wakefulness compared to the control groups both in the daytime and nighttime and decreasing the activity of these same neurons reduced wakefulness in the nighttime. Blocking neurotransmitter release in glutamatergic neurons significantly reduced wake in the nighttime. The ionotropic receptor mutants had significantly less wake in the nighttime than their respective genetic background controls.
Conclusion:
The results show the following: glutamate is indeed a wake-active neurotransmitter in Drosophila; there is a major time of day effect associated with loss of glutamatergic neurotransmission; and it is a major wake-active neurotransmitter in the nighttime.
Angiotensin II infusion increases plasma erythropoietin levels via an angiotensin II type 1 receptor-dependent pathway.
Angiotensin-converting enzyme inhibitors (ACEIs) have been shown to lower ...hematocrit and erythropoietin (EPO), but a direct link between angiotensin II (Ang II) and EPO in humans has not been shown.
Placebo or Ang II was infused for six hours in nine healthy male volunteers with and without blockade of the Ang II subtype 1 receptor (AT1R). EPO concentrations were measured 3, 6, 12, and 24 hours after the start of the infusion.
Ang II raised the mean arterial pressure by about 20mm Hg. Consistent with the known diurnal variation, EPO levels rose significantly (P ≤ 0.02) during the day in all groups. During Ang II infusion, EPO levels rose to significantly higher levels after 6 and 12 hours compared with placebo 9.9 ± 3.5 vs. 7.2 ± 3.1 mU/mL (3 h, P = NS); 16.9 ± 4.5 vs. 8.8 ± 3.7 mU/mL (6 h, P = 0.01); 17.0 ± 8.6 vs. 11.1 ± 4.7 mU/mL (12 h, P = 0.01) and returned to baseline after 24 hours (7.9 ± 3.8 vs. 10.6 ± 8.6 mU/mL, P = NS). With AT1R blockade, blood pressure remained normal during Ang II infusion, and EPO levels were never significantly different from placebo 6.8 ± 4.8, 10.5 ± 5.6, 13.1 ± 9.0, and 12.4 ± 10.1 mU/mL at 3, 6, 12, and 24 h after infusion, respectively, P = NS.
Ang II increases EPO levels in humans. This increase requires the participation of AT1R.
Genetic variation in coding regions is of strong interest for biologists as it represents an important factor that drives evolution. To analyse polymorphic loci, researchers usually rely on commonly ...used typing techniques such as cloning, SSCP, DGGE or RSCA. However, there are potential pitfalls in screening multi-allelic templates, which are mainly the formation of sequence chimeras during PCR amplification, and mosaic sequences during cloning. One of the most challenging genomic regions to explore is the Major Histocompatibility Complex (
MHC), which codes for peptide-binding proteins of the vertebrate's adaptive immune system and is well known for its exceptional polymorphism. We compared the effect of two different PCR amplification approaches in a study of the
MHC class IIB genes of the three-spined stickleback (
Gasterosteus aculeatus). One approach used standard PCR conditions and the other a combination of several measures to eliminate PCR artefacts. In both approaches, the amplicons obtained were cloned and sequenced. In the first, established approach, 24% of the clones represented artefacts, while in the second approach the number of artefacts were reduced ten-fold. Furthermore, it enabled easy differentiation between real alleles and artificial sequences. We also analysed the potential effects of such artefacts in genetic analysis and evolutionary interpretation, and found a slight reduction in the signature of positive selection and an increase in recombination events. Consequently, we strongly recommend to apply the new PCR approach described in this study when genotyping
MHC or other polymorphic genes.
Severe renal artery stenosis may cause renovascular hypertension; in case of bilateral narrowing or in a stenotic solitary or transplant kidney, renal insufficiency (ischemic renal disease) or rarely ...pulmonary flash edema may occur. In most cases arteriosclerotic disease is the underlying cause; less prevalent are the various manifestations of fibromuscular disease. Renal artery stenosis may be treated by revasularization, using either percutaneous (balloon angioplasty, stenting) or rarely open surgical procedures, both with excellent primary patency rates. However, randomized trials of renal artery angioplasty or stenting in patients with arteriosclerotic lesions have failed to demonstrate a longer-term benefit with regard to hypertension control and renal dysfunction over medical management alone. Careful patient selection is essential to maximize the potential benefit (e.g., in patients with refractory hypertension, progressive renal failure or recurrent pulmonary flash edema).
Background
This study aimed to clarify whether children with neurocardiogenic syncope (NCS) differ from healthy control subjects in baseline heart rate variability (HRV) and in their response to ...orthostatic stress induced by active standing and tilt table.
Methods
This study analyzed the difference between 55 children with a history of NCS or presyncopal symptoms (PS) and healthy control subjects. Measurements included short-term HRV during resting position, tilt table testing, and active standing. Time and frequency domain HRV parameters were computed.
Results
Both the NCS and PS children differed significantly from healthy control subjects during resting position. During tilt table testing, nearly all NCS and PS subjects differed significantly from the control group in calculated HRV parameters. Moreover, for the low-frequency power and total power, the confidence intervals did not overlap.
Conclusions
The findings suggest that chronic autonomic differences exist between healthy children and patients with NCS and PS. These changes could be detected even by short-term HRV recordings. The tilt table maneuver provoked the most prominent differences between the groups. Low-frequency power and total power during tilt table testing helps to detect children with NCS.
Certain physiological changes caused by aerobic exercise can alter the pharmacokinetics of some drugs. A systematic review of the pharmacokinetic changes that can affect drugs as a result of aerobic ...exercise is provided. Eleven commonly used drugs are reviewed for their potential interaction with exercising patients. Serum concentrations of two beta-blocking agents, atenolol and propranolol, and one antibiotic, doxycycline, have shown to increase as a result of exercise. No pharmacokinetic changes have been found in exercising patients taking carvedilol or verapamil. Patients who exercise after taking digoxin experience a decreased digoxin serum concentration with an increased skeletal muscle concentration. The clearance of theophylline has been shown to decrease resulting in an increase in plasma half-life during exercise. The risk of hypoglycaemia may increase when patients with diabetes mellitus inject insulin into a muscle just prior to exercising that muscle. Increasing physical activity in patients taking warfarin has been shown to decrease the international normalised ratio. Much is still unknown regarding the interactions that exist between exercise and drug therapy. More studies need to be completed in this area before definite conclusions are made and clinical relevance can be established. Clinicians should be aware that the potential for such interactions exists, especially for drugs with a narrow therapeutic range and in patients who participate in extreme sporting activities.
We study the fluorescence of nanodiamond ensembles as a function of static external magnetic field and observe characteristic dip features close to the zero field with potential for magnetometry ...applications. We analyze the dependence of the feature’s width and the contrast of the feature on the size of the diamond (in the range 30 nm–3000 nm) and on the strength of a bias magnetic field applied transversely to the field being scanned. We also perform optically detected magnetic resonance (ODMR) measurements to quantify the strain splitting of the zero-field ODMR resonance across various nanodiamond sizes and compare it with the width and contrast measurements of the zero-field fluorescence features for both nanodiamonds and bulk samples. The observed properties provide compelling evidence of cross-relaxation effects in the NV system occurring close to zero magnetic fields. Finally, the potential of this technique for use in practical magnetometry is discussed.
OBJECTIVE:
To describe the pharmacology, pharmacokinetics, efficacy, and safety of a fixed-dose combination of aspirin and extended-release (ER) dipyridamole indicated for the secondary prevention of ...stroke.
DATA SOURCES:
Published articles and abstracts were identified from a MEDLINE search (1966–December 1999) using the search terms dipyridamole, aspirin, antiplatelet, antiaggregation, and stroke prevention. Pertinent articles written in English were considered for review. Additional articles were identified from the references of retrieved literature.
STUDY SELECTION AND DATA EXTRACTION:
Studies including a combination of aspirin/dipyridamole in human subjects were evaluated. Emphasis was placed on randomized, controlled trials.
DATA SYNTHESIS:
Aspirin is a platelet inhibitor that works by inhibiting platelet cyclooxygenase, which reduces the production of thromboxane A2. Dipyridamole is a platelet inhibitor that is thought to work in part by inhibiting platelet cyclic-3',5'-adenosine monophosphate and cyclic-3',5'-guanosine monophosphate phosphodiesterase. The active metabolite of aspirin, salicylic acid, is highly bound to plasma protein and has a plasma half-life of two to three hours. Dipyridamole is also highly bound to plasma proteins, and the ER formulation has a plasma half-life of 13 hours. The first European Stroke Prevention Study (ESPS-1) found the combination of aspirin/dipyridamole to be superior to placebo in the prevention of stroke and transient ischemic attack (TIA). The ESPS-1, however, did not include an aspirin-only treatment arm. Therefore, it was unclear whether the combination of aspirin/dipyridamole was superior to aspirin alone. As a result, a second trial was conducted that included treatment arms of aspirin alone, ER dipyridamole alone, combination therapy, and placebo. The combination of aspirin 25 mg plus ER dipyridamole 200 mg twice daily was shown in the ESPS-2 to be significantly better than either agent given individually in preventing stroke and TIAs (p < 0.001).
CONCLUSIONS:
The American College of Chest Physicians (ACCP) recommends aspirin 50–325 mg/d to be the initial antiplatelet of choice for the prevention of atherothrombotic cerebral ischemic events. However, with the favorable results of the ESPS-2, it may be appropriate to substitute aspirin/ER dipyridamole for aspirin alone as the drug of choice. This combination appears to have a favorable adverse effect profile. The relative effectiveness of aspirin/ER dipyridamole compared with clopidogrel and ticlopidine has yet to be determined. If alternative antiplatelet therapy is needed, the ACCP recommends clopidogrel rather than ticlopidine because of its lower incidence of adverse effects. The ACCP further states that the combination of aspirin plus dipyridamole may be more effective than clopidogrel; these agents have a similarly favorable adverse effect profile.
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