Possibilities for frequency adjusted heart stimulation

In the sick sinus syndrome, in sinu-atrial conduction defects or in atrial flutter or fibrillation a stress-adapted, frequency-adapted stimulation cannot be obtained by the processing of the atrial potential. Here one depends on partly extracardiac parameters which contain informations about the metabolic and stress situation, respectively. A survey of the parameters for a frequency-adapted stimulation discussed at present is given and a critical valuation of them is carried out. It is shown that all parameters up to now experimentally and clinically, respectively, tested are more or less problematic and that the way out of the difficulty most consist in deriving the controlled variable for a stress adapted stimulation rate from several parameters.     

Value of small bowel double contrast enema in clinical interventions

The double contrast enema is the most effective morphological screening method for the evaluation of the whole small bowel. Its sensitivity is 85%, its specifity 96.7%. In specific clinical problems the number of pathological roentgen findings rises: from 34.4% when all indications are taken into consideration to 58% in indications specific to the small intestine such as Morbus Crohn or the malabsorption syndrome. Search for tumours and the double contrast of the small bowel in unclear gastro-intestinal bleeding are unproductive. The weak point of this screening method is the lower part of the small intestine. Therefore, the selective peroral or retrograde analysis of the terminal ileum supplement the contrast method. A precondition for good results is an adequate technical standard. Besides the clinical results some technical results are therefore discussed such as contrast medium quantities, examination and X-ray time, radiation exposure and influences on the image quality.     

Testosterone suppresses protective responses of the liver to blood-stage malaria

Testosterone induces a lethal outcome in otherwise self-healing blood-stage malaria caused by Plasmodium chabaudi. Here, we examine possible testosterone effects on the antimalaria effectors spleen and liver in female C57BL/6 mice. Self-healing malaria activates gating mechanisms in the spleen and liver that lead to a dramatic reduction in trapping activity, as measured by quantifying the uptake of 3-mum-diameter fluorescent polystyrol particles. However, testosterone delays malaria-induced closing of the liver, but not the spleen. Coincidently, testosterone causes an approximately 3- to 28-fold depression of the mRNA levels of nine malaria-responsive genes, out of 299 genes tested, only in the liver and not in the spleen, as shown by cDNA arrays and Northern blotting. Among these are the genes encoding plasminogen activator inhibitor (PAI1) and hydroxysteroid sulfotransferase (STA2). STA2, which detoxifies bile acids, is suppressed 10-fold by malaria and an additional 28-fold by testosterone, suggesting a severe perturbation of bile acid metabolism. PAI1 is protective against malaria, since disruption of the PAI1 gene results in partial loss of the ability to control the course of P. chabaudi infections. Collectively, our data indicate that the liver rather than the spleen is a major target organ for testosterone-mediated suppression of resistance against blood-stage malaria.     

Proliferative Responses of Rabbit Lymphocytes to Pasteurella multocida Decrease with Prolonged Immunization

Peripheral blood and splenic lymphocytes from rabbits immunized with Pasteurella multocida by various schedules were stimulated to undergo blast transformation in vitro in response to this antigen. Repeated immunizations suppressed this response.     

Immunoglobulin level in donor blood reactive for antibodies to human immunodeficiency virus.

Blood samples from 98 asymptomatic volunteer blood donors, including 55 that were reactive for antibodies to human immunodeficiency virus (HIV) in Western blot (WB) assay, were tested for levels of immunoglobulin G (IgG), IgM, and titer of antibodies to HIV, cytomegalovirus, and herpes simplex virus. Levels of IgG were significantly elevated (P less than or equal to 0.001) in donors with specific anti-HIV reactivity. A total of 69% of donors with anti-HIV had IgG levels of greater than or equal to 12 mg/ml, and 44% had IgG levels of greater than or equal to 14.5 mg/ml. Levels of IgM were not significantly different among WB-reactive and nonreactive donors. The titer of anti-HIV was significantly (P less than 0.02) correlated with IgG levels among donors reactive in the WB assay. Elevation of IgG, however, was not significantly associated with the presence of anticytomegalovirus or anti-herpes simplex virus antibodies. The data show that elevation of IgG may represent an early manifestation of HIV infection before the development of clinical symptoms of acquired immunodeficiency syndrome.     

Levels of prostaglandins in human endometrium during the normal menstrual cycle

The levels of prostaglandins in the human endometrium throughout the normal menstrual cycle were measured by bioassay. The identity of prostaglandin F_2α and prostaglandin E₂ in endometrial tissue extracts was established by combined gas chromatography/mass spectrometry.

The levels of prostaglandin F_2α and prostaglandin E₂ are low during the proliferative phase of the cycle (10-25 ng/100 mg tissue). Prostaglandin F_2α rises significantly during the luteal phase to levels of 65-75 ng/100 mg of tissue. Prostaglandin E₂ levels are similar to prostaglandin F_2α levels in the proliferative phase but remain lower during the luteal phase. The prostaglandin E₂ level is highest at menstruation (52 ng/100 mg tissue). The implications of these findings are discussed in relation to the menstrual process and to the steroid hormonal changes during the cycle.