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Copyright of Egyptian Journal of Histology is the property of Egyptian Journal of Histology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Egyptian Journal of Histology is the property of Egyptian Journal of Histology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The internal anal sphincter (IAS) plays an important role in the maintenance of anorectal continence and in the pathophysiology of constipation and incontinence. Failure of a full-term newborn to pass meconium within the first 24 h should raise a suspicion of intestinal obstruction. However, the causes of functional intestinal obstruction in infants are still unclear; however, one cause might be immaturity of the IAS.This study aimed at illustrating the developmental changes in IAS in guinea pigs of different ages.Forty-one guinea pigs were selected and divided into four groups. They were sacrificed and the rectoanal canal specimens were dissected at the appropriate time from each group as follows: group I - from embryos in the third trimester; group II - from animals on their first postnatal day; group III - from animals aged 4 weeks; and group IV - from animals aged 16 weeks. The rectoanal canal specimens was prepared for histological and immunohistochemical studies. Morphometric analysis was also performed.Thickness of the IAS increased with advancing age, whereas that of the connective tissue component decreased. Moreover, α-smooth muscle actin filaments increased with age. There was also age-related development of the enteric nervous system, especially the myenteric plexus in the rectoanal junction region.Results of the current study revealed pronounced developmental changes in the histological structure of guinea pig IAS. Therefore, development of the IAS might have a possible role in the functional intestinal obstruction seen in preterm and full-term infants. [ABSTRACT FROM AUTHOR]

Low-level laser irradiation (LLLI) has been shown to modulate the proliferation of endothelial cells. Helium-neon (He-Ne) laser is the best type of laser for biostimulation. The aim of the present study was to investigate the direct stimulatory effect of LLLI on the proliferative potential of human umbilical vein endothelial cell line in vitro.This study included five groups: group I (zero time after seeding He-Ne laser irradiation), group II (24▒h after seeding He-Ne laser irradiation), group III (48▒h after seeding He-Ne laser irradiation), group IV (96▒h after seeding He-Ne laser irradiation), and group V (cumulative He-Ne laser irradiation every 48▒h for a period of 6 days). Each group was subdivided into three subgroups: subgroup a (control), subgroup b (1.77▒J/cm2 He-Ne laser irradiation), and subgroup c (3.54▒J/cm2 He-Ne laser irradiation). A continuous wave He-Ne laser, emitting a wavelength of 632.8▒nm with a power output of 5▒mW was used for irradiating the cells. A growth curve was constructed for each group to determine the growth parameters.The most efficient cellular response to LLLI was in subgroup Ic depending on the population doublings achieved, followed by subgroup Ib. Therefore, the early the use of He-Ne laser irradiation for the cultured cells, the more the cellular stimulation and proliferation. Meanwhile, their delayed use resulted in less cellular stimulation and proliferation. Moreover, the results showed that 1.77 and 3.54▒J/cm2 of He-Ne laser irradiation were always stimulatory for endothelial cells either significantly or insignificantly.The present study showed that 1.77 and 3.54▒J/cm2 of He-Ne laser irradiation stimulated human umbilical vein endothelial cell line proliferation. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) in the bone marrow retain the capacity to proliferate and differentiate along multiple connective tissue lineages, including cartilage. The aim of this study is to induce cultured-expanded rat MSCs derived from bone marrow to express the morphology and protein production of chondrocytes.The characteristics of MSCs and chondrogenic cells were determined morphologically, immunohistochemically, and by transmission electron microscopy.MSCs were spindle shaped with irregular processes, and were positive for CD44 and CD105 and negative for CD34. Chondrogenesis is induced by culturing the rat MSCs in monolayer in the presence of a defined chondrogenic medium that includes 100 nm dexamethason and 10 ng/ml TGF-β3. The results showed that the cells changed their morphology within 5 days and became positive for collagen II within 3 weeks after differentiation. Also, the chondrogenic cells showed the structural organelles of protein-synthesizing cells by electron microscopy.These results indicated that TGF-β3 can induce rat MSCs to differentiate in vitro into chondrogenic cells. Therefore, chondrogenic cells cultured from bone marrow sources are potentially valuable for repairing injured cartilage. [ABSTRACT FROM AUTHOR]

Peyer's patches (PPs) are essential elements of the gut-associated lymphatic tissue that are involved in defense against pathogens that may be colonizing the gut and are also involved in oral food tolerance otherwise food allergy occurs.This research aimed to study the postnatal development of PPs in male albino rats.Fifty male albino rats were divided into five groups of 10 animals each. Group 1 (1 day old), group 2 (1 week old), group 3 (2 weeks old), group 4 (4 weeks old), and group 5 (8 weeks old). The terminal part of the ileum was dissected out and processed for light and electron microscopic examinations. Paraffin sections were stained with hematoxylin and eosin, periodic acid-Schiff and immunohistochemical staining was carried out for detection of CD3 and CD20 (markers of T and B lymphocytes, respectively). Quantitative morphometric study was conducted, and the results were statistically analyzed.Early during postnatal period, PPs appeared as small epithelial elevations overlying small aggregates of lymphocytes. The size of PPs and lymphocytic cell density increased gradually to reach maximum by adult age (group 5). Most of the lymphocytes were of the T type early postnatally followed by increase in B lymphocytes during the following age groups. Germinal centers started to appear in group 4 and in the adult age group. The epithelium covering the surface of PPs showed reduced number of goblet cells, and M cells started to appear from the age of 2 weeks onward.Epithelium covering the PPs showed structural changes matching with functional specialization such as gradual reduction of goblet cells and appearance of M cells. In addition, an association was found between the times of onset of M cells and B-lymphocytic follicles in PPs. [ABSTRACT FROM AUTHOR]

Restoration of the blood flow and reintroduction of oxygen after deprivation accelerate tissue injury. The insult of intestinal ischemia reperfusion (I/R) is not necessarily limited to the intestine itself, but involves the severe destruction of the other tissues because of the reperfused oxygenated blood. Many reports indicated that I/R is an important inciting event in the pathogenesis of multiple organ system failure, which is the leading cause of death in critically ill patients. So, the aim of this study was to evaluate the possible protective role of pyrrolidine dithiocarbamate (PDTC) on liver and small intestinal injury following mesenteric ischemia reperfusion.The study was performed on forty adult male albino rats weighting 200-250 gm that were divided into three groups. Group I: Control animals which divided into untreated and sham operated (10 animals each). Group II: Intestinal ischemia reperfusion animals, which were underwent one hour ischemia and two hours reperfusion. Group III: Animals received 200 mg/kg PDTC intraperitoneally one hour before intestinal ischemia reperfusion procedure. Parts were taken from the liver and jejunum were processed for histological examination and other jejunal parts for scanning electron microscopic examinations (SEM). Immunohistochemical expression of NF-κB factor in the liver was investigated.A variety of changes were observed in the jejunum ranging from epithelial separation and loss of the brush border to cellular lysis, destruction of villi, cellular infiltrations, hemorrhages and basal glandular ulcerations. The liver showed areas of edema fluid, hemorrhages, mononuclear cellular infiltration and increased expression of NF-κB factor.Treatment with PDTC resulted in improvement in most of the histological changes induced by intestinal ischemia-reperfusion in the jejunum and liver. Therefore, PDTC can be considered as an effective protecting agent during intestinal ischemia reperfusion and can be used clinically in such instances. [ABSTRACT FROM AUTHOR]