Search results for "Secretor"

Effects of Constant and Doublet Frequency Electrical Stimulation Patterns on Force Production of Knee Extensor Muscles

2016

International audience; This study compared knee extensors' neuromuscular fatigue in response to two 30-minute stimulation patterns: constant frequency train (CFT) and doublet frequency train (DFT). Fifteen men underwent two separate sessions corresponding to each pattern. Measurements included torque evoked by each contraction and maximal voluntary contractions (MVC) measured before and immediately after the stimulation sessions. In addition, activation level and torque evoked during doublets (Pd) and tetanic contractions at 80-Hz (P80) and 20-Hz (P20) were determined in six subjects. Results indicated greater mean torque during the DFT stimulation session as compared with CFT. But, no dif…

Electron microscopic study on the larval and adult corpus allatum of Oncopeltus fasciatus dallas (insecta, heteroptera)

1973

1. The ultrastructure of the corpora allata of last larval instars and adults of Oncopeltus was studied. The unpaired gland undergoes submicroscopic alterations and shows signs of degradation in old animals. The organ is partly covered and penetrated by corpus cardiacum tissue. Axons with different types of neurosecretory granules form synaptoid contacts with the corpus allatum cells.

Prostasome-like vesicles stimulate acrosome reaction of pig spermatozoa

2007

Abstract Background The presence of small membranous particles characterizes the male genital fluids of different mammalian species. The influence of semen vesicles, denominated prostasomes, on sperm functional properties has been well documented in humans, but their biological activity is scarcely known in other species. The present work investigated prostasome-like vesicles in pig semen for their ability to interact with spermatozoa and to affect acrosome reaction. Methods Prostasome-like vesicles have been isolated from pig seminal plasma by high-speed centrifugation and Sephadex G-200 gel chromatography. Morphology of purified vesicles has been checked by scanning electron microscopy wh…

How to Make a Vesicle: Coat Protein-Membrane Interactions

2018

Comparing the different morphotypes of a fish pathogen - implications for key virulence factors in Flavobacterium columnare

2014

Background: Flavobacterium columnare (Bacteroidetes) is the causative agent of columnaris disease in farmed freshwater fish around the world. The bacterium forms three colony morphotypes (Rhizoid, Rough and Soft), but the differences of the morphotypes are poorly known. We studied the virulence of the morphotypes produced by F. columnare strain B067 in rainbow trout ( Onconrhynchus mykiss ) and used high-resolution scanning electron microscopy to identify the fine structures of the cells grown in liquid and on agar. We also analysed the proteins secreted extracellularly and in membrane vesicles to identify possible virulence factors. Results: Only the Rhizoid morphotype was virulent in rain…

Mild dehydration: a risk factor of urinary tract infection?

2003

Bacterial growth in the urinary tract is usually prevented by host factors including bacterial eradication by urinary and mucus flow, urothelial bactericidal activity, urinary secretory IgA, and blood group antigens in secretions which interfere with bacterial adherence. Bacterial eradication from the urinary tract is partially dependent on urine flow and voiding frequency. Therefore, it seems logical to postulate a connection between fluid intake and the risk of urinary tract infections (UTIs). However, experimental and clinical data on this subject are conflicting. Experimental studies concerning the effect of water intake on susceptibility and course of UTIs were predominantly performed …

Secretory breast carcinoma with metastatic sentinel lymph node

2006

Abstract Background Secretory mammary carcinoma is a rare breast neoplasia originally described in children but sometimes also found in adults. It presents a more favourable outcome than more common histological types of breast carcinoma; published literature in fact reports only a few cases with axillary lymph node metastases and only four cases with distant metastases. Clinical presentation In this paper we report a rare case of secretory breast carcinoma with axillary lymph node metastases in a 33-year-old woman. To our knowledge, this is the first case of secretory carcinoma involving biopsy of the sentinel lymph node and investigation of the e-cadherin expression. We found positivity f…

Vascular Senescence: A Potential Bridge Between Physiological Aging and Neurogenic Decline

2021

The adult mammalian brain contains distinct neurogenic niches harboring populations of neural stem cells (NSCs) with the capacity to sustain the generation of specific subtypes of neurons during the lifetime. However, their ability to produce new progeny declines with age. The microenvironment of these specialized niches provides multiple cellular and molecular signals that condition NSC behavior and potential. Among the different niche components, vasculature has gained increasing interest over the years due to its undeniable role in NSC regulation and its therapeutic potential for neurogenesis enhancement. NSCs are uniquely positioned to receive both locally secreted factors and adhesion-…

Intraepidermal formation of Merkel cells in xenografts of human fetal skin.

1990

An experimental transplantation model using human fetal skin was applied to approach the question of the embryologic origin of human Merkel cells. Palmar and plantar skin from five fetuses, between 8 and 11 weeks of estimated gestational age (EGA), was xenografted to subcutaneous beds of nude mice. After 4 or 8 weeks of growth, biopsies were taken from these xenografts and examined for the presence of Merkel cells, using immunocytochemistry with antibodies specific for simple epithelial-type cytokeratins and neuron-specific enolase (NSE) as well as using electron microscopy. Skin from the same fetuses at the time of transplantation was screened in the same way. In all fetuses, no (or very s…

Merkel cells in ontogenesis of human nails

1993

Digital skin of human fetuses is known to contain a particularly high concentration of Merkel cells. Using antibodies against the simple epithelial cytokeratins (CK) 18 and 20, which are sensitive and specific Merkel cell markers, we studied immunohistochemically the main adnexal structure of digital skin, the nail anlage, in human fetuses (9-22 weeks of gestation) for the presence of Merkel cells. As early as week 9 some clustered Merkel cells were detected in the early matrix primordium. In specimens of week 12-15, abundant Merkel cells were found in the nail anlagen, particularly in the epithelium of the proximal nail-fold and the dorsal and ventral side of the apex region. In contrast, …