Evaluation of the Adherence of Candida Species to Urinary Catheters

Catheter-associated urinary tract infections (CAUTIs) are the most common kind of nosocomial infection. Recent years have seen a significant increase in numbers of infections caused by yeasts of the genus Candida. The adherence of a microorganism to the host surface is a decisive factor in the success of colonization and the pathogenesis of infection. The objective of this work was to evaluate the adherence of species of the genus Candida to urinary catheters. In vitro adherence to the sections of latex and silicon catheters of Candida albicans and Candida parapsilosis were studied. Adherence was measured by counting the number of adhering viable cells and the results were expressed as Colonies Forming Units per mL. The results demonstrated that the latex catheter facilitated adherence more than the silicon catheter (p < 0.01). The adherence of the C. albicans was significantly greater than C. parapsilosis on latex, but it was similar on silicon.     

Cellular distribution and bioactivity of the key steroidogenic enzyme,cytochrome P450side chain cleavage,in sensory neural pathways

Neurosteroids are steroids produced within the nervous system. Based on behavioural responses evoked in animals by synthetic steroid injections, several studies suggested neurosteroid involvement in important neurophysiological processes. These observations should be correlated only to neuroactive effects of the injected steroids. Neurosteroids mostly control the CNS activity through allosteric modulation of neurotransmitter receptors within concentration ranges used by neurotransmitters themselves. Therefore, neurosteroid production within pathways controlling a neurophysiological process is necessary to consider neurosteroid involvement in that process. Because of the increasing speculation about pain modulation by neurosteroids based on pharmacological observations, we decided to clarify the situation by investigating neurosteroidogenesis occurrence in sensory pathways, particularly in nociceptive structures. We studied the presence and activity of cytochrome P450side chain cleavage (P450scc) in rat pain pathways. P450scc-immunoreactive cells were localized in dorsal root ganglia (DRG), spinal cord (SC) dorsal horn, nociceptive supraspinal nuclei (SSN) and somatosensory cortex. Incubation of DRG, SSN or SC tissue homogenates with [3H]cholesterol yielded the formation of radioactive metabolites including [3H]pregnenolone of which the synthesis was reduced in presence of aminogluthetimide, a P450scc inhibitor. These first neuroanatomical and neurochemical results demonstrate the occurrence of neurosteroidogenesis in nociceptive pathways and strongly suggest that neurosteroids may control pain mechanisms.     

Effects of injury and progesterone treatment on progesterone receptor and progesterone binding protein 25-Dx expression in the rat spinal cord

Progesterone provides neuroprotection after spinal cord injury, but the molecular mechanisms involved in this effect are not completely understood. In this work, expression of two binding proteins for progesterone was studied in intact and injured rat spinal cord: the classical intracellular progesterone receptor (PR) and 25-Dx, a recently discovered progesterone membrane binding site. RT-PCR was employed to determine their relative mRNA levels, whereas cellular localization and relative protein levels were investigated by immunocytochemistry. We observed that spinal cord PR mRNA was not up-regulated by estrogen in contrast to what is observed in many brain areas and in the uterus, but was abundant as it amounted to a third of that measured in the estradiol-stimulated uterus. In male rats with complete spinal cord transection, levels of PR mRNA were significantly decreased, while those of 25-Dx mRNA remained unchanged with respect to control animals. When spinal cord-injured animals received progesterone treatment during 72 h, PR mRNA levels were not affected and remained low, whereas 25-Dx mRNA levels were significantly increased. Immunostaining of PR showed its intracellular localization in both neurons and glial cells, whereas 25-Dx immunoreactivity was localized to cell membranes of dorsal horn and central canal neurons. As the two binding proteins for progesterone differ with respect to their response to lesion, their regulation by progesterone, their cellular and subcellular localizations, their functions may differ under normal and pathological conditions. These observations point to a novel and potentially important role of the progesterone binding protein 25-Dx after injury of the nervous system and suggest that the neuroprotective effects of progesterone may not necessarily be mediated by the classical progesterone receptor but may involve distinct membrane binding sites.     

Analysis and characteristics of multiple types of human 17beta-hydroxysteroid dehydrogenase

Androgens and estrogens are not only synthesized in the gonads but also in peripheral target tissues. Accordingly, recent molecular cloning has allowed us to identify multiple types of 17β-hydroxysteroid dehydrogenases (17β-HSD), the key and exclusive enzymes involved in the formation and inactivation of sex steroids. However, only one form, namely, type 3 17β-HSD, is responsible for pseudohermaphroditism in deficient boys. To date, seven human 17β-HSDs have been isolated and characterized. Although they catalyze substrates having a similar structure, 17β-HSDs have very low homology. In intact cells in culture, these enzymes catalyze the reaction in a unidirectional way — types 1, 3, 5 and 7 catalyze the reductive reaction, while types 2, 4 and 8 catalyze the oxidative reaction. It is noteworthy that rat type 6 17β-HSD also catalyzes the reaction in the oxidative direction. In this report, we analyze the different characteristics of the multiple types of human 17β-HSD.     

Sexual Differentiation of the Brain as a Manifestation of Its Plasticity

This review analyzes the published data and authors' own results on the roles of hormones and neurotransmitters in the formation of structural and functional sex-related dimorphism of the brain within the early ontogenesis period. Proof is presented in favor of the concept that classic neurotransmitters function as inductors of nerve cell differentiation in the process of individual development of the brain. Neurochemical mechanisms of the hormone–transmitter interaction in the process of sexual differentiation of the brain within pre- and/or post-natal periods are considered.     

Effects of oral aluminum on essential trace elements metabolism during pregnancy

The present study was conducted to assess in rats the effects of oral aluminum (Al) exposure on calcium (Ca), magnesium (Mg), manganese (Mn), copper (Cu), zinc (Zn), and iron (Fe) accumulation and urinary excretion. Three groups of plug-positive Sprague-Dawley (SD) rats were given by gavage 0, 200, and 400 mg/kg/d of Al(OH)₃ on gestational days 1–20. Three groups of nonpregnant female SD rats of the same age received Al(OH)₃ by gavage at the same doses for 20 consecutive days. At the end of the treatment period, 24-h urine samples were collected for analysis of Al and essential elements. Subsequently, all animals were sacrificed and samples of liver, bone, spleen, kidneys, and brain were removed for metal analyses. With some exceptions, the urinary amounts of Al, Mn, and Cu excreted by pregnant animals as well as the urinary levels of Al excreted by nonpregnant rats were higher in the Al-treated groups than in the respective control groups. Although higher Al levels were found in the liver of pregnant rats, the concentrations of Al in the brain of these animals were lower than those found in the same tissues of nonpregnant rats. With regard to the essential elements, tissue accumulation was most affected in pregnant than in nonpregnant animals. In pregnant rats, the hepatic and renal concentrations of Ca, Mg, Mn, Cu, Zn, and Fe, as well as the levels of Ca in bone, and the concentrations of Cu in brain were significantly higher in the Al-exposed groups than in the control group. According to the current results, oral Al exposure during pregnancy can produce significant changes in the tissue distribution of a number of essential elements.     

A non-surgical rat model of foreign body-associated urinary tract infection with Pseudomonas aeruginosa

This study established a rat model of foreign body-associated urinary tract infection. A spiral polyethylene tube (PT) was placed transurethrally into the bladder without surgical manipulation, followed by transurethral inoculation with Pseudomonas aeruginosa. The persistence of P. aeruginosa in the kidneys and bladder was significantly enhanced by placement of the PT, whereas the bacteria were eliminated rapidly from the urinary tract in the animals without the PT. Scanning electron microscopy revealed a thick biofilm on the surface of the PT from the early stage of infection. Histopathologically, acute pyelonephritis was followed by chronic renal inflammation as well as continuous and sporadic polymorphonuclear leukocyte accumulation and hemorrhage in the pelvis and adjacent tissues, suggesting continuous ascending introduction of the bacteria from the biofilm adhering to the PT. We believe our model simulates the pathophysiology of foreign body-associated urinary tract infection characterized by biofilm formation on the surface of a foreign body.