Assessment of placental function by estimation of testosterone in plasma after an intravenous injection of dehydroepiandrosterone sulphate (DHAS)

The response of plasma testosterone to an intravenous injection of 50 mg dehydroepiandrosterone sulphate (DHAS) was measured in 22 pregnant women. In 15 women with uncomplicated pregnancies a rapid and steep increase of plasma testosterone was observed, most women having their maximum testosterone value recorded as soon as 5 minutes after the injection. Three women with preeclampsia had delayed maximum values. They delivered infants of low birth-weight or with low Apgar scores. One woman with pre-eclampsia had a normal response and gave birth to a healthy infant of normal birth-weight. Out of 3 women with intrauterine growth retardation (IUGR) 2 had an abnormal and 1 a normal response. It is concluded that the plasma response of testosterone to an injection of DHAS is a reflection of placental function.     

Cochlear vascular histology in animals exposed to noise

Summary The regularly occurring cochlear vessels in the external wall and spiral lamina were studied in the guinea pig and chinchilla following exposure to various types and durations of noise. A soft-surface specimen technique with or without injection of a contrast medium into the vascular system was used, and the occurrence of specified vascular parameters was assessed using phase-contrast microscopy. Noise does not seem to result in any extraordinary vascular pathology, but a slight, overall decreased blood supply to the cochlea and localized changes depending on cochlear turn are suggested.This investigation was supported by the Labour Environment Protection Fund (78/69:2)Presented at the 17th Workshop on Inner Ear Biology in Stockholm, June 23–25, 1980     

Effect of Glyceryltrinitrate and 8–Br–cGMP on Tension and Phosphorylase a Activity in Vascular Smooth Muscle

Abstract: The aim of the present study was to examine the effect of glyceryltrinitrate (GTN) and 8–Br–cGMP on tension and cytosolic calcium concentration in pre–contracted bovine mesenteric arteries (BMA). The activity of glycogen phosphorylase a was used as a measure of the cytosolic calcium concentration. The activity of this enzyme is regulated by the cytosolic calcium concentration and/or cAMP. Since the cAMP level was not found to be affected by GTN–treatment, the use of phosphorylase a activity to monitor changes in the cytosolic calcium concentration can be justified. The vessels were contracted with phenylephrine (10 μM) or 100 mM K⁺–depolarization, which caused an increase in phosphorylase a activity. Addition of 1 μM GTN to the phenylephrine–contracted vessels resulted in a 3–4–fold rise in intracellular cGMP level, which was accompanied by a large decrease in tension and phosphorylase a activity. The K⁺–depolarized vessels, on the other hand, were largely resistant to the relaxant action of GTN, and there was only a slight reduction of the phosphorylase a activity. In phenylephrine–contracted vessels, made tolerant to GTN by incubation at elevated pH in the presence of GTN (0.44 mM), no changes in tension and phosphorylase a activity were seen after stimulation with a test dose of GTN (1 μM). The cGMP response was also markedly blunted in the tolerant vessels. Relaxation of phenylephrine–contracted BMA induced by 8–Br–cGMP (0.5 mM) was also accompanied by a reduction in phosphorylase a activity. The close association between the relaxation of BMA and the reduction in phosphorylase a activity suggests that GTN and 8–Br–cGMP exert their effects mainly by reducing the cytosolic free calcium concentration although a contributing effect on the contractile apparatus can not be excluded     

The relaxant effect of glyceryltrinitrate on isolated human peripheral vein and its relation to cyclic GMP metabolism

The relaxant effect of glyceryltrinitrate (GTN) on human vena saphena magna was studied in vitro. Vessels contracted by serotonin (0.25 microM) and phenylephrine (0.1 mM) were relaxed to the same extent (EC50 = 10 microM) by GTN, whereas in 100 mM K+-depolarized vessels the relaxation was significantly lower. The relaxant effect produced by GTN was preceded by an elevation of cyclic guanosine-3',5'-monophosphate (cGMP). For 0.1 mM GTN there was a 3-fold increase in cGMP after 3 min. A correlation between relaxation and increase in cGMP was established. When GTN was combined with dipyridamole (5 microM) the relaxant effect of GTN was significantly greater (EC50 = 0.1 microM). Phosphodiesterase inhibition, as a possible mechanism behind the observed better relaxation for the combination (GTN+dipyridamole), is briefly discussed. In conclusion, the relaxant effect of GTN on isolated human vena saphena magna seems to be dependent on the contractile stimuli used, increased by the addition of DIP and to be mediated via cGMP.     

The effects of noise on histological measures of the cochlear vasculature and red blood cells: a review

This paper compiles the results from seven experiments which have investigated noise exposure effects on histological measures of the cochlear vasculature and red blood cells. Two of these studies included at least two experimental conditions and all evaluated numerous histological parameters in several cochlear vessels. The combined results suggest that noise has a consistent general effect of reducing apparent cochlear blood flow as indicated by decreased RBC density, increased aggregation of RBCs, increased variability in RBC density, decreased number of RBC columns, increased vessel lumen irregularity and encroachment of perivascular cells upon the lumen wall. When considered at the level of the individual vessels, however, inconsistent results were observed. Fewer effects were noted in experiments which permitted animals to survive after the noise exposure than in those which sacrificed the animals immediately. Impulse noise resulted in more frequent vascular sequelae than did continuous noise. Further, impulse noise more frequently influenced vessels of the external wall than did continuous noise.     

Methodological aspects of some inner ear vascular techniques.

Modifications of preparation technique assessing cochlear vasculature together with suggestions regarding their applicability to various types of research projects are presented. Detailed information is given regarding the 'soft-surface' dissection and preparation technique along with selected parameters for evaluating the cochlear vasculature. Some basic requirements for any histological technique studying the inner ear blood supply are suggested.     

Inhibitory effects of different retinoids (vitamin A analogues) on the stimulated rat liver guanylate cyclase activity

Vitamin A and its analogues show the ability to prevent malignant cell transformation on induction with different carcinogens, such as nitrosamines. Cyclic GMP has been proposed as a positive modulator of malignant cell growth and the cGMP-forming enzyme guanylate cyclase is strongly stimulated by e.g. nitrosamines. In this study, we found that retinylacetate and retinal were very potent inhibitors of the stimulated guanylate cyclase. When a series of structurally different retinoids were tested in the same system, a wide range of inhibitory activity on guanylate cyclase was found for the different retinoids with some being completely ineffective. The most potent inhibitor was retinylacetate. Furthermore, the inhibitory profile of the retinoids on the guanylate cyclase did not seem to correlate to their in vivo activity as antineoplastic agents, as described in the literature. We therefore conclude that there does not exist a general connection between the anticancer activity and the guanylate cyclase inhibition of the retinoids. However, it can not be excluded that the guanylate cyclase inhibition might be of importance for the antineoplastic activity for some of the retinoids.     

Anaphylactic reactions to sunflower seed

We report on four patients sensitized to sunflower seed. Three of them developed anaphylaxis and one chronic bronchial asthma. All four patients reacted the first time sunflower seeds were ingested, and all had kept cage birds fed on sunflower seeds. Therefore, the route of sensitization was probably by inhalation of airborne sunflower seed allergens. Investigation of this type of hypersensitivity in 84 atopic patients showed that only three patients were RAST-positive, indicating that this allergy is fairly uncommon. On the other hand, when atopic persons are exposed to cage birds, the rate of sensitization is rather high, as indicated by the fact that in this category 79% were skin prick positive and 21% were unequivocably RAST positive to sunflower seed.     

Outcome of pregnancy among women living near petrochemical industries in Sweden

The association between exposure to emissions from petrochemical industries and outcome of pregnancy was examined in a small area of Sweden. The study was based largely, but not entirely, on questionnaire data and evaluated the pregnancies which occurred between the end of 1963 and 30 June 1981 for a sample of 1400 women born between 1935 and 1960. In addition to the questionnaire study, information on all infants born between 1973 and 1981 in this area was obtained from central registers. The miscarriage rate was slightly elevated in the exposed area (OR = 1.15, 0.75-1.76, 95% confidence interval). While a statistically significant increase in miscarriages was found for a small subset of women who worked for one of the petrochemical companies during pregnancy (OR = 6.6, 2.3-19.2), the overall results did not support the hypothesis that ambient community exposures were associated with an increased risk of unfavourable pregnancy outcome.     

Agonistic properties of anti-B cell antibodies purified on staphylococcal protein A may be due to contaminating protein A.

Some antibodies directed to cell surface receptors may mimic the physiological ligands by inducing the transmission of activation or growth signals. Such agonistic antibodies have proven very useful when studying functional properties of various receptor molecules on, e.g., lymphoid cells. However, while investigating the agonistic effects on tonsillar B cells of the anti-CD43 monoclonal antibody (mAb) D4B11 and the anti-CD40 mAb S2C6, we made some observations which emphasize the need for caution when using antibodies purified by protein A affinity chromatography. Both antibody preparations were found to elicit changes in the intracellular free calcium concentration ([Ca2+]i) as well as promoting proliferation of phorbol ester activated cells. However, a closer analysis showed that the increase in [Ca2+]i could be attributed to soluble staphylococcal protein A (SpA) desorbed during antibody purification. By using pure soluble SpA, we were able to show that nanogram amounts were sufficient to increase [Ca2+]i by a mechanism that involved both a mobilization from intracellular stores and an influx across the B cell membrane. A similar effect on cytosolic Ca2+ in B cells was also noted for streptococcal protein G (protein G), another bacterial component used for antibody purification. However, in contrast to SpA, protein G had little effect on cell proliferation. These observations suggest that the presence of trace amounts of SpA or protein G in antibodies purified on these bacterial components may lead to incorrect interpretations of the agonistic properties of such antibodies. When the above findings were taken into account, it was found that the CD43 mAb D4B11, like the CD40 mAb S2C6, stimulated growth of B cells without causing any measurable increase in [Ca2+]i. Both CD40 and CD43 may thus be coupled to signalling pathways which do not involve breakdown of membrane phosphoinositides.