Prevalence of Chlamydia specific antibodies among obstetric and gynecological outpatients in Gondar, north-west Ethiopia.

A total of 533 obstetric and gynecological outpatients who visited the dedicated clinics in Gondar, Ethiopia, between April and August 1995 were investigated for Chlamydia-specific antibodies. Relevant epidemiological and clinical data were collected using a pretested questionnaire, clinical examinations and laboratory tests. Earlier, using an antigen specific ELISA technique, we had reported that only 33 (6%) of these women were positive for C. trachomatis in cervical swabs. In this study, we evaluated the prevalence of C. trachomatis-specific antibodies in serum samples of the same patients collected at the time the cervical swabs were taken. Employing a genus-specific ELISA for the detection of chlamydial LPS antibodies, 90% of the sera were found to be positive for IgG, while 49% of the sera contained IgA and 28% IgM antibodies. For 436 of the positive sera, species specificity of the antibodies was determined by means of a micro-immunofluorescence assay. Antibodies against C. trachomatics were present in 75% and antibodies against C. pneumoniae in 69% of these sera. Forty-nine percent of the patients carried antibodies against both species. The antibody based assay estimated that 13.9% of the patients had acute genital chlamydial infection (antigen specific IgM and the simultaneous presence of C. trachomatis specific IgG, IgM and IgA). C. trachomatis antigen detection in cervical swabs apparently underestimated the real frequency of acute infections. Seroprevalence of C. pneumoniae antibodies in the Ethiopian patients was similar to that in industrialized countries.

[3H-leucine incorporation into the secretory cells of the murine mammary gland under the action of adrenomimetics]. / Vkliuchenie 3H-leitsina v sekretornye kletki molochnoi zhelezy myshei pri deistvii adrenomimetikov.

Although there is some evidence suggesting the involvement of the sympathoadrenal system in the mammary gland function, the precise mechanism by which adrenergic agents may influence galactopoietic processes is largely unknown. The aim of this study was to investigate whether the reported decrease in milk and organic substance content after catecholamine administration might be due to the inhibition of protein synthesis. For that purpose, the incorporation of 3H-leucine into the secretory cells of the mammary gland of lactating mice under the influence of the alpha-adrenoceptor agonist phenylephrine and the beta-adrenoceptor agonist isoproterenol, respectively, was studied by light microscopic autoradiography. Tissue radioactivity as a whole was measured by liquid scintillation counting. It was shown that neither the alpha- nor the beta-agonist simultaneously given with the labeled amino acid were able to change the amount of radioactivity taken up by the mammary gland. From this result it is concluded that a transitory increase in catecholamine concentration in the blood has no effect on mammary gland protein synthesis.

On the blood-brain barrier to peptides: effects of immobilization stress on regional blood supply and accumulation of labelled peptides in the rat brain.

Tritiated arginine-vasopressin (AVP), desglycinamide-vasopressin (DGAVP), chicken gonadotropin releasing hormone (GnRH) or carbetocin were injected intracarotidally into rats exposed to a restraint stress for 60 min. The peptide accumulations were determined in 9-13 brain regions and anterior pituitary. In separate experiments the cerebral blood flow was measured. The blood supply to the brain was decreased in stressed animals as indicated by: 1. significant decrease (17-50%) of cerebral blood flow; 2. diminished accumulation of tritiated AVP in the regions lacking a blood-brain barrier (BBB). Consequently, the values of peptide accumulation were corrected for the changed blood supply. Compared with control animals, restraint stress induced a higher accumulation of AVP (+41%), DGAVP (+60%), carbetocin (+81%) and GnRH (+104%).

Transfer of [3H]leucine across the blood-brain barrier at high blood-side oxytocin concentrations in normal and morphine-dependent rats.

The effects of circulating oxytocin on permeability of the blood-brain barrier (BBB) to L-[3H]leucine were studied in anaesthetized rats using the intracarotid, single pass, bolus injection technique. After bolus intracarotid oxytocin injection (10(-9) M), there were no differences in [3H]leucine uptake, compared with controls, in any of eight brain regions with a 'tight' BBB (olfactory bulb, frontal cortex, visual cortex, corpus striatum, hippocampus, thalamus, hypothalamus and colliculi) or in BBB-free, 'leaky' structures (pineal gland, choroid plexus, neuro-intermediate pituitary, anterior pituitary). [3H]leucine uptake by the 'leaky' structures was 2.4x and 2.6x uptake by 'tight' regions in the oxytocin and control groups respectively. In morphine-dependent rats, naloxone increased oxytocin secretion 28-fold within 5 min, but did not affect [3H]leucine uptake for any BBB-protected brain region or BBB-free 'leaky' structure. Accumulation of [3H]leucine was 8.3x and 7.0x greater in the 'leaky' structures than in the 'tight' regions in the naloxone and control groups respectively; [14C]inulin accumulation by each 'tight' region (measured simultaneously with [3H]leucine to determine the vascular space) was not affected by naloxone. It is concluded that even very high blood plasma concentrations of oxytocin do not affect BBB permeability for leucine. It is unlikely that altered BBB permeability, at least for amino acids, contributes to CNS changes during naloxone-provoked morphine withdrawal.

The influence of exogenous oxytoxin on labelling of secretory epithelium of mouse mammary gland by [3H]leucine, evidenced by autoradiography.

It has been suggested that oxytocin, besides its milk-ejecting activity, is also involved in the hormonal regulation of the mammary gland secretory cells. The available data, however, are conflicting. In this study two independent experiments, separated by a certain time interval show that oxytocin intravenously administered to mice at days 10-14 of lactation diminished the incorporation of [3H]leucine into the mammary gland tissue by 32 and 53 per cent, respectively. The neurohormone was co-injected with the tracer amino acid. The radioactivity taken up by the secretory cells was estimated by light microscopic autoradiography. The autoradiograms were evaluated by visual silver grain counting. Tissue radioactivity was measured by liquid scintillation counting. A milk stasis in the mammary gland induced by depriving the mice of suckling two hours before tracer injection had no influence on the secretory activity of the glandular cells. It is assumed that oxytocin has a direct effect on the milk-producing cells, and that the reduction in measurable radioactivity caused by the neurohormone may be due to an accelerated intracellular passage of labelled milk proteins.

Age-related pathophysiology of the blood-brain barrier in heat stress.

The possibility that the blood-brain barrier (BBB) might play an important role in the pathophysiology of heat stress (HS) has been examined in young (age 8-9 weeks) and adult (age 24-32 weeks) rats. Exposure of young rats to 4 h HS at 38 degrees C in a biological oxygen demand (BOD) incubator (relative humidity 47-50%, wind velocity 20-26 cm/sec, simulating the environmental conditions of Varanasi, India, during the month of June) resulted in a marked hyperthermia (41.7 +/- 0.23 degrees C) and behavioral symptoms. In these animals there was a profound increase in the permeability of the BBB to Evans blue-albumin (EBA) (464%) and to 131I-sodium iodide (515%), accompanied by a marked increase in the brain water content (4%), of the levels of serotonin (5-hydroxytryptamine, 5-HT) in plasma (687%) and in brain (267%) and a pronounced reduction (30%) in cerebral blood flow (CBF). Morphological examination using light- and electron-microscopy revealed profound neuronal changes associated with a marked increase in glial fibrillary acidic protein (GFAP) and in vimentin immunoreactivities, together with a substantial reduction in myelin basic protein (MBP) immunostaining in the brain. These changes were more pronounced in the brain-stem reticular formation, pons and medulla region. On the other hand, exposure of adult animals to the same intensity of HS resulted in mild or no changes in BBB permeability, content of brain water and 5-HT in the plasma and brain, CBF or other cellular changes.(ABSTRACT TRUNCATED AT 250 WORDS)

On the blood-brain barrier to peptides: specific binding of atrial natriuretic peptide in vivo and in vitro.

Using the intracarotid bolus injection technique, a saturable binding of [125I]atrial natriuretic peptide (ANP) was found in 8 blood-brain barrier (BBB)-protected rat brain regions as well as in the pineal gland, choroid plexus, neurointermediate and anterior lobes of the pituitary, i.e. structures lacking a BBB. The presence of specific ANP binding on the BBB, here shown for the first time by an in vivo approach, was evidenced concomitantly in vitro by incubation of isolated microvessels. A single-class high affinity binding without regional differences was obtained with Kd = 0.23 nM and Bmax = 120 fmol/mg protein. From that a density of 1,400 binding sites per endothelial cell was calculated, thought to be localized predominantly in the luminal membranes. In the in vivo study, the portion of the extracted peptide that, under the conditions used, may have crossed the BBB by passive diffusion amounted to less than 0.4% of the labeled ANP administered. ANP itself did not change the tightness of the BBB to the non-diffusible reference molecule [14C]inulin. In the BBB-free areas, ANP enhanced the inulin space by nearly 50%.

Autoradiographic demonstration of glucocorticoid receptors in the intermediate lobe of the rat pituitary transplanted to the anterior eye chamber.

It is a general belief that the intermediate lobe of the pituitary, in contrast to the anterior pituitary, is devoid of glucocorticoid receptors. However, Antakly et al. (1985) using immunocytochemistry, demonstrated the presence of this receptor in intermediate lobe cells deprived of the hypothalamic innervation. It was the aim of the present study to confirm this finding by auto-radiography, i.e., using an independent method. The neurointermediate lobe of adult male Wistar rats was syngeneic transplanted to the anterior eye chamber. The recipient rats were adrenalectomized 19 days after grafting and injected with [3H]corticosterone 5 days later. After a survival time of 60 min, autoradiograms were prepared by thaw-mount technique and quantitatively evaluated by silver grain counting. Beside the classical targets, anterior pituitary and hippocampal stratum pyramidale, the intraocular transplants showed a nuclear accumulation of radioactivity. This was abolished in rats treated for competition with an excess of unlabelled corticosterone prior to tracer application. No such receptor binding was found in the normotopic intermediate lobe and in the diaphragm studied as a non-target reference. Thus, this study confirmed that the glucocorticoid receptor gene is expressed if the tissue is grafted into an ectopic site.

Blood-brain barrier and peptides.

The brain is both the source and the recipient of peptide signals. The question is: Do endogenous, blood-borne peptide molecules influence brain function? Brain regions with the tight capillaries of the blood-brain barrier (BBB) extract low but measurable amounts of labeled peptide molecules from an intracarotid bolus injection. In the rat, the extraction fractions of beta-casomorphin-5, DesGlyNH2-arginine-vasopressin, arginine-vasopressin, lysine-vasopressin, oxytocin, gonadoliberin, substance P, and beta-endorphin, studied in this laboratory, range from 0.5% (substance P) to 2.4% (arginine-vasopressin). Extraction varies little among the 15 examined brain regions. As shown for arginine-vasopressin, the extracted peptides may be bound in part to specific binding sites located on the luminal membrane of the tight endothelial cells. Transport of peptide molecules across the BBB cannot be ruled out, but it is unlikely that endogenous peptides pass the BBB in physiologically significant amounts. In contrast, in brain regions with leaky capillaries, e.g., selected circumventricular organs including the pineal gland, neurohypophysis, and choroid plexus, the peptide fraction extracted approaches that of water. Within the circumventricular organs, the peptide molecules actually reach the cellular elements of the tissue. However, no studies definitively show that peptides reach neurons in the deeper layers of the brain. On the other hand, blood-borne peptides influence the BBB permeability by altering the transport of essential substances. The effect may be mediated by specific peptide binding sites located at the luminal membrane of the endothelium. It is possible that the effect of peptides on the BBB is necessary for proper brain function.(ABSTRACT TRUNCATED AT 250 WORDS)

On the blood-brain barrier to peptides: accumulation of labelled vasopressin, DesGlyNH2-vasopressin and oxytocin by brain regions.

After intracarotid injection of 125I-arginine vasopressin (AVP), 125I- or 3H-lysine vasopressin (LVP), 3H-DesGlyNH2-arginine vasopressin (DGAVP), and 125I- or 3H-oxytocin (OXT), the accumulation of radioactivity was determined in 13 to 18 brain regions and anterior pituitary in rats. Calculated extraction by tight capillary regions amounts to about 1-2% independently of the peptide doses injected (4 X 10(-4) to 5 X 10(-9) mol-1). This indicates a low but measurable extraction of labelled peptides which furthermore is nonsaturable. Among brain regions with tight capillaries, the extraction does not vary obviously. Blood-brain barrier (BBB)-free regions extract up to 30 fold more peptide than BBB-protected regions and the extraction varies considerably between individual regions. Within BBB-free regions, the peptides passed the leaky capillary endothelium, but there is no evidence for a penetration to deeper layers of the brain. It is concluded that endogenous blood-borne peptides cannot pass brain barriers in physiologically significant amounts. This does not exclude a possibility that passive transport of minute but effective amounts might occur if high pharmacological amounts of peptides are injected peripherally. But, as shown, none of the peptides studied possesses properties that favour its passage across the BBB.

On the blood-brain barrier to peptides: [3H]gonadotropin-releasing hormone accumulation by eighteen regions of the rat brain and by anterior pituitary.

After intracarotid injection of [3H]gonadotropin-releasing hormone ([3H]GnRH) the mean accumulation of radioactivity per unit wet weight of 18 investigated brain samples and the anterior pituitary was 0.38 +/- 0.11% g-1 of the injected tracer dose. This indicates a low but measurable brain uptake of the peptide. The brain uptake of [3H]GnRH in blood-brain barrier (BBB)-protected regions is 5% of that of separately investigated [3H]OH. In BBB-free regions the accumulation of radioactivity was more than 25-fold higher than in BBB-protected regions. The accumulation of [3H]GnRH among regions with BBB varies less than among regions with leaky endothelia. The data presented for [3H]GnRH are similar to those for other peptides so far investigated.

The presence of steroids in larval and mature brook lampreys (Lampetra planeri Bloch).

The presence of steroids was investigated by radioimmunoassay - mass spectrometry in serum and homogenates of gonads and presumed adrenocortical (pro- and opisthonephric) tissue of larval and mature brook lampreys (Lampetra planeri Bloch) of both sexes. Pregnenolone was detected in all tissue samples studied whereas androstenedione could be identified only in presumed adrenocortical tissue from male and female mature animals as well as in testis. Testosterone was present in testis of adult lampreys and in sera of larval and adult animals.

On the blood-brain barrier to peptides: [3H]beta-casomorphin-5 uptake by eighteen brain regions in vivo.

After intracarotid injection of [3H]beta-casomorphin-5 (beta CM5) in rats, the accumulation of radioactivity was determined in 18 brain regions and the anterior pituitary. The relative accumulation in all regions significantly exceeded that of [3H]inulin by a factor of 2.5, indicating a low but measurable brain uptake of the peptide. In blood-brain barrier-free areas, the accumulation of radioactivity was 15-fold higher than in blood-brain barrier-protected areas. The relative accumulation was not dependent on the total beta CM5 concentration in the range of 0.3-1.1 microM, and was not depressed by 400 microM L-tyrosine. We conclude that beta CM5, like other peptides, is accumulated in the blood-brain barrier-free areas to a relatively high but differing degree, whereas in the areas with a tight endothelium the accumulation is relatively low and nearly uniform. A binding to endothelial cells may contribute to the low accumulation of beta CM5, especially in blood-brain barrier-protected areas.

[The Harderian gland--target for cyclic nonapeptide neurohypophyseal hormones. Autoradiographic studies on the rat (author's transl)]. / Die Hardersche Drüse--ein Zielorgan für Neurohypophysenhormone. Autoradiographische Untersuchungen an der Ratte.

Among autoradiograms of different tissues prepared after intravenous injection of 3H-tyrosine oxytocin into male white rats, only those of the kidney and the Harderian gland, an exocrine gland in the orbit of most terrestrial vertebrates, displayed a saturable labelling, i.e., pretreatment of the rats with an excess of unlabelled oxytocin led to a significantly lowered tissue content of radioactivity. Liquid scintillation analysis confirmed this result. Moreover, besides the kidney only the Harderian gland proved to be labelled in autoradiograms prepared after intracarotid injection of 125I-lysine vasopressin into male white rats. The intensity of this label is enhanced in Brattleboro rats. The results strongly suggest that the Harderian gland represents a hitherto not recognized target for posterior pituitary cyclic nonapeptide hormones. Concerning the physiological role these hormones may play in the gland, the speculation is put forward that oxytocin like its role in the mammary gland might be involved in the regulation of Harderian gland secretory processes.

The reticular formation of lampreys (Petromyzonidae)--a target area for exohypothalamic vasotocinergic fibres.

The octapeptide vasotocin, which is formed in the classical neurosecretory nuclei of lampreys (Petromyzonidae), is transported, bound to the carrier protein neurophysin, not only to the neurohypophysis but also to various other regions of the brain via exohypothalamic fibres. A target area of this exohypothalamic vasotocinergic system is, in the brook lamprey (Lampetra planeri Bloch), a relatively well circumscribed area in the isthmus region of the rhombencephalic tegmentum motoricum, which is called area lateralis tegmenti. In this area, which belongs to the reticular formation, the vasotocinergic fibres form synaptic contacts with nerve cell perikarya and processes. The vesicles contained in the fibres were identified, ultrahistochemically, as neurophysin vesicles. They correspond to the neurophysin vesicles observed in the neurohypophysis of the same species. The functional significance of the vasotocinergic supply to portions of the reticular formation in lampreys is open to discussion.