Quantification of in-plane motion of the coronary arteries during the cardiac cycle: Implications for acquisition window duration for MR flow quantification

Motion of the coronary arteries during the heart cycle can result in image blurring and inaccurate flow quantification by MR. This condition applies particularly for longer acquisition windows that are typical of breath-hold coronary flow measurements. To determine the sensitivity of the technique to in-plane motion of different coronary arteries, the temporal variation in coronary position was measured in a plane perpendicular to the proximal portion of the vessel. The results indicated the presence of substantial displacement of the coronary arteries within the cardiac cycle, with a magnitude of motion approximately twice as large for the right as for the left coronary arteries. An estimation of the resulting vessel blurring was calculated, showing that the duration of the acquisition window for high spatial resolution coronary flow acquisitions should be less than 25 to 120 msec, depending on the specific coronary artery studied. In addition, these data specify optimal acquisition window placement for high resolution coronary angiography.     

Histamine release in the course of elective conventional cholecystectomy in aged patients: Problems in defining release in relation to specific intraoperative events

The effectiveness of an H₁ ^–+H₂-prophylaxis against perioperative acute pseudoallergic reactions in which histamine is involved, and against postoperative complications the incidence of which may be increased by these reactions, was the central problem of a randomized trial in 162 aged patients during elective conventional cholecystectomy. As main endpoint it was planned to use the systemic histamine release reaction, as it already had been defined for the conscious and anaesthetized human subject. However, it had to be reassessed and redefined for the intraoperative period after improvement of the plasma histamine assay and new findings about stress-induced histamine release and the kinetics of histamine release during certain phases of operation.Intraoperative release is, at present, defined solely as an increase of plasma histamine values after a particular action (phase of operation). It includes criteria concerning plasma histamine changes either in comparison to the base value before surgery or to the preceding value before the last surgical action. Histamine elevations must exceed the last value by more than 3 standard deviations of the analytical error (i.e. 200% if value <0.25 ng/ml=" and=" 40%=" above).=" basic=" requirements=" for=" the=" histamine=" assay=" (quality=" control),=" correct=" sample=" taking=" and=" appropriate=" preparation=" have=" to=" be=" fulfilled=" over=" the=" whole=" trial=" period.=" when=" these=" criteria=" were=" applied=" to=" the=" 162=" patients=" an=" overall=" incidence=" of=" histamine=" release=" during=" cholecystectomy=" of=" 55.6%=" was=" found=" with=" 9.7–20%=" during=" an=" individual=" phase=" of=" operation.=" the=" data=" of=" this=" study,=" performed=" under=" routine=" conditions,=" with=" a=" sufficient=" number=" of=" patients=" with=" elevated=" risk=" and=" event=" controlled=" plasma=" histamine=" values,=" lead=" to=" a=" better=" understanding=" of=" intraoperative=" histamine=" release,=" its=" incidence=" and=">     

The clinical and biological signs of histamine release during induction of anaesthesia and preparation of the surgical patient: A farewell party for the classical manifestations of anaphylaxis

The clinical manifestations of histamine release and their clinical relevance are still matter of considerable debate among anaesthesiologists whereas surgeons have no opinion at all. In a series of six clinical-experimental trials a gold standard for histamine release was established, the term histamine release reaction was determined, and a combination of clinical predictors was created for assessing the effectiveness of a prophylaxis with histamine H₁+H₂-antagonists.After the construction of the gold standard elevated plasma histamine, in the first three trials the experimental validation, the selection of standard variables for a clinical test and the validation with authentic histamine was accomplished. In three further trials this test was applied to several histamine releasers which have been commonly used for induction of anaesthesia and preparation of a surgical patient, namely, the hypnotic propanidid, the muscle relaxant atracurium, and the plasma substitute Haemaccel. In these trials, H₁+H₂-sensitive variables were also selected for a diagnostic classification of histamine release reactions.     

The immunofluorescence-microscopical evidence of insulin and glucagon in transplantated isolated Langerhans' islets in diabetic rats and dogs (author's transl)]

With the histochemical immunofluorescence technique were demonstrated the insulin and glucagon in the transplantated isolated Langerhans' islets in the liver at diabetic rats and dogs. Further on were tested the diabetic metabolic level with aid of clinico-chemical methods during the period of investigation (blood glucose, serum insulin, glucose tolerance test). It was found that after transplantation, 1 year by the rats and more than 8 weeks by the dogs, is existing a normoglycemic level. In the transplanted islets were seen a good immunofluorescence of insulin in the B cells and the glucagon in the A cells in all investigated stages.     

Changed visuomotor transformations during and after prolonged microgravity

A series of step-tracking experiments was conducted before, during, and after a 3-week space mission to assess the effects of prolonged microgravity on a non-postural motor-control task. In- and post-flight accuracy was affected only marginally. However, kinematic analyses revealed a considerable change in the underlying movement dynamics: too-small force and, thus, too-low velocity in the first part of the movements was mainly compensated by lengthening the deceleration phase of the primary movement, so that accuracy was regained at its end. The observed in-flight decrements in peak velocity and peak acceleration point to an underestimation of mass, in agreement with the re-interpretation hypothesis of Bock et. al. Post-flight no reversals of the in-flight changes (negative aftereffects) were found. Instead, there was a general slowing down, which could be due to post-flight physical exhaustion.     

Evidence for reduced traumatization during laparoscopic versus conventional cholecystectomy: Different changes in histamine levels related to special phases of operation

The role of histamine in injury due to trauma or surgical treatment is more than doubtful after more than 70 years of investigation. A comparison of histamine released during conventional versus minimal invasive surgery seems especially useful to elucidate the role of histamine in such important events of the daily clinical life.Histamine is released during conventional cholecystectomy in patients of high age, a special group of risk for perioperative morbidity and mortality. In animal experiments, it was shown that this histamine release is due to technical differences between the two types of operation. Hence histamine release seems to be a suitable parameter for the stimulus-induced approach to stress and trauma. Histamine is localized in high concentrations especially in abdominal tissues. After its release it may cause direct actions at a susceptible myocardium, pulmonary parenchyma or gastrointestinal mucosa. However, histamine release is also a proxy variable for mast cell irritation, stimulation and mediator release. This should not be forgotten when the role of histamine is discussed in shock, ARDS, DIC and other clinically relevant or even life-threatening events in routine surgical care.     

Searching for archaic contribution in Africa

Abstract

Context: Africa’s role in the narrative of human evolution is indisputably emphasised in the emergence of Homo sapiens. However, once humans dispersed beyond Africa, the history of those who stayed remains vastly under-studied, lacking the proper attention the birthplace of both modern and archaic humans deserves. The sequencing of Neanderthal and Denisovan genomes has elucidated evidence of admixture between archaic and modern humans outside of Africa, but has not aided efforts in answering whether archaic admixture happened within Africa.

Objectives: This article reviews the state of research for archaic introgression in African populations and discusses recent insights into this topic.

Methods: Gathering published sources and recently released preprints, this review reports on the different methods developed for detecting archaic introgression. Particularly it discusses how relevant these are when implemented on African populations and what findings these studies have shown so far.

Results: Methods for detecting archaic introgression have been predominantly developed and implemented on non-African populations. Recent preprints present new methods considering African populations. While a number of studies using these methods suggest archaic introgression in Africa, without an African archaic genome to validate these results, such findings remain as putative archaic introgression.

Conclusion: In light of the caveats with implementing current archaic introgression detection methods in Africa, we recommend future studies to concentrate on unravelling the complicated demographic history of Africa through means of ancient DNA where possible and through more focused efforts to sequence modern DNA from more representative populations across the African continent.     

Localization of corticotropin-releasing activity in the rat hypothalamus

Hypothalamic nuclei were removed from frozen sections of rat brain and examined for their corticotropin-releasing activity. The highest concentration was measured in the median eminence. In addition there was significantly more activity detected in the nuclei paraventricularis, supraopticus, suprachiasmaticus and arcuatus than in the other nuclei.     

Fiber optic probe for polarized reflectance spectroscopy in vivo: design and performance

We present the design and construction of a fiber optic probe for elastic light scattering spectroscopy in vivo with polarized excitation and polarization sensitive detection. The performance of the fiber probe is evaluated using a suspension of polystyrene spheres placed atop a diffusely scattering substrate, and it demonstrates that the size-dependent characteristics of the scatterers can be extracted in the presence of a highly diffusely scattering background using a linear combination of forward and backward Mie scattering components of the scatterers. Subsequently, Mie theory calculations are performed over a broad range of diagnostically relevant parameters of nuclei-mean diameter, size distribution, and relative refractive index-to understand how the polarized reflectance measurements with the fiber probe can be used to extract morphological information about epithelial tissue. Finally, the feasibility of in vivo measurements with the fiber optic based polarization sensitive light scattering spectroscopy is demonstrated.     

T-cell-activation inhibitors in rheumatoid arthritis

As rheumatoid arthritis (RA) is a chronic inflammatory disabling disease and a cure is not available, optimisation of therapeutic strategies is mandatory. Within recent years many new details of the inflammatory cascade(s) have been elaborated, leading to new therapeutic options such as neutralisation of tumour necrosis factor-alpha (TNFalpha). T-cell inhibition is another new approach to the treatment of RA. However, it is important to note two points: first, the role of T lymphocytes in the initiation and/or perpetuation of RA is still debated controversially. Second, there are few truly T-cell-specific agents that have proven to be effective and are established in the treatment of inflammatory disorders. Leflunomide may be considered one such agent; another in development is the fusion protein CTLA4-Ig. From a clinical perspective, studies demonstrating efficacy of these agents might represent the strongest support for a role of T cells in RA. In addition to leflunomide and CTLA4-Ig, therapeutic agents with activity against T cells, including anti-CD4 antibodies, cyclosporin, tacrolimus and T-cell receptor (TCR)-Vbeta-chain vaccination strategies, have been studied in patients with RA. Combination therapies including any of these T-cell-activation inhibitors with non-T-cell-specific agents such as methotrexate, antimalarials or anti-TNFalpha biologicals may prove the most effective strategies in controlling this complex disease.