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At least 685 records · Page 38Linked to original sources
PubMed1991

Poor development of outer dense fibers as a major cause of tail abnormalities in the spermatozoa of asthenoteratozoospermic men.

For a reasonable analysis of sperm motility, consideration should be given to the morphology of the flagellum. Among various tail disturbances, the present paper describes a structural shaft defect that is characterized by variations in diameter, poor outline and/or lacking endpiece. Electron microscopical examinations, especially the negative staining technique, have shown that in addition to membrane alterations there is one essential cause for the limited extension of the outer dense fibres. This disturbance may be of genetic origin or due to toxic or inflammatory influences. Further molecular biological studies are required to detect the actual cause of this defect, for which there is so far no adequate therapy.

Humans↗
PubMed2005

Curli fibers are required for development of biofilm architecture in Escherichia coli K-12 and enhance bacterial adherence to human uroepithelial cells.

Sessile bacteria show phenotypical, biochemical, and morphological differences from their planktonic counterparts. Curli, extracellular structures important for biofilm formation, are only produced at temperatures below 30 C in Escherichia coli K-12 strains. In this report, we show that E. coli K-12 can produce curli at 37 C when grown as a biofilm community. The curli-expressing strain formed more biofilms on polyurethane sheets than the curli-deficient strain under growth temperatures of both 25 C and 37 C. Curli are required for the formation of a three-dimensional mature biofilm, with characteristic water channels and pillars of bacteria. Observations by electron microscopy revealed the presence at the surfaces of the curli-deficient mutant in biofilm of flagella and type I pili. A wild-type curli-expressing E. coli strain significantly adhered to several lines of human uroepithelial cells, more so than an isogenic curlideficient strain. The finding that curli are expressed at 37 C in biofilm and enhance bacterial adherence to mammalian host cells suggests an important role for curli in pathogenesis.

Bacterial Adhesion↗
PubMed2001

Newly developed immobilized polymyxin B fibers improve the survival of patients with sepsis.

BACKGROUND: Sepsis and septic shock are still major causes of morbidity and mortality in spite of the availability of powerful and broadly active antibiotics. METHODS: A prospective, open and randomized trial of the effect of immobilized polymyxin fibers (PMX-F) on the survival of patients with sepsis throughout a follow-up period of 28 days or until discharge, if earlier, was carried out. Ninety-eight patients were included who met at least 4 of the criteria for systemic inflammatory response syndrome due to infection. The patients were classified into three groups based on their Acute Physiology and Chronic Health Evaluation (APACHE) II score. RESULTS: The overall survival rate was significantly improved by using PMX-F compared to the control group (41 vs. 11%) (p = 0.002). In patients with an APACHE II score less than 20, treatment with PMX-F was shown to improve outcome (65 vs. 19%) (p = 0.01). In cases of more severe sepsis with an APACHE II score of 20-29, PMX-F still maintained efficacy in improving outcome (40 vs. 11%) (p = 0.04). However, PMX-F treatment did not improve the survival rate in patients with an APACHE II score of greater than 30 (survival rate 7 vs. 0%) (p = 0.59). CONCLUSION: From these results, it is concluded that treatment with PMX-F in patients with sepsis is effective and prolongs the survival rate when applied at an early stage of sepsis. However, in severe sepsis, this therapy does not improve the survival rate.

APACHE↗
PubMed1980

Pattern of development of ascending and descending fibers in embryonic spinal cord of chick: II. A correlation with behavioral studies.

Studies on the embryonic spinal cord were extended to include the development of the ascending and descending fibers from the brachial level. This study was designed to correlate morphological development of the intersegmental system with physiological and behavioral observations of early embryonic behavior. Chick embryos were analyzed prior to day 6 of incubation, which is before closure of the reflex arc and arrival of supraspinal inputs to the embryonic spinal cord. Injections of 3H-proline were made in the upper brachial level of chick embryos of stages 27--29 (5--6 days). The location of radioactive label in the marginal zone was analyzed autoradiographically to show the projection of labeled axonal flow from the site of injection. The majority of the labeled axons in the marginal zone was in the first 2--3 segments in both ascending and descending directions from the site of injection. By stage 27 (day 5), ascending labeled axons extended to the upper cervical level and labeled descending axons extended only about 4--5 segments to the upper thoracic level. By stage 29 (day 6) labeled ascending axons extended into the medulla oblongata, and labeled descending axons still extended only 4--5 segments caudally. These studies (Parts I and II) show that at stage 27 (day 5) there was considerable axoplasmic flow of radioactive label in the marginal zone from the lumbar to the brachial plexus but not in the opposite direction from the brachial to the lumbar plexus. Also, axoplasmic flow of label initially extended from the brachial plexus to the medulla oblongata sometime between stages 27--29. It was concluded that the intersegmental system of the embryonic spinal cord is well developed by day 6 of incubation and provides the neuro-anatomical substrate for early embryonic behavior.

Afferent Pathways↗
PubMed1993

The frequent occurrence of closely packed intrafusal myotubes during the early postnatal development of muscle spindles in the Chinese hamster.

The formation of intrafusal muscle fibers of developing muscle spindles in the tenuissimus muscle of the Chinese hamster was examined by electron microscopy from birth to 7 days postnatal. At birth, at least two nuclear bag myotubes with a small aggregation of nuclei were already recognizable within a spindle capsule, establishing side-to-side contact with each other without the intercalation of a basal lamina. By the third postnatal day, most muscle spindles contained a full adult set of four intrafusal myotubes effected by the formation of nuclear chain myotubes due to the fusion of myoblasts. The intrafusal myotubes were usually enclosed in a common basal lamina and closely apposed without an interposing basal lamina, thus forming a muscle bundle. Sensory endings were thereby confined to the outer surface of the muscle bundle. After the third day, closely packed intrafusal myotubes generally separated into independent muscle fibers which were innervated by sensory endings and ensheathed in attenuated inner capsule cells. Pairings of fibers and sensory cross terminals between fibers were frequently found in the equatorial region. These phenomena suggest that the incomplete separation of the bundled myotubes at an early stage of postnatal development may persist into adulthood.

Animals↗