Developmental stages and growth of the proventriculus of post-hatching Muscovy duck: Light and electron microscopic study

The present study was implemented to provide comprehensive information on the developmental sequence of the proventriculus of Muscovy ducks by gross examination, macro-micrometric analysis and by using light microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). Samples from 55 healthy post-hatching Muscovy ducks of both sexes ranging from 1 to 60 days old. The proventriculus began cranially opposite to the cranial end of the liver at 1-15 days old, but in front this level at 30 and 60 days old. Morphometrically, the length of the proventriculus was increased by about four folds while weight by 19 folds at 60 days old when compared with those at one day old. Scanning electron microscopy of the proventricular lumen at one day old exhibited numerous small mostly rounded irregularly distributed openings of the glands, but uniformly distributed and surrounded by closely packed concentrically arranged mucosal folds resembling a rosette shape at the older ages. Histologically, in all studied stages, rounded, elongated oval or polymorphic shaped lobules of the proventricular glands were occupied within the muscularis mucosa. The tubuloalveolar secretory units lined with secretory (oxyntico-peptic) cells with variable shapes had secretory granules increased by the development. Numerous argyrophilic endocrine cells were demonstrated away from the glandular lumen at older ages. Transmission electron microscopy revealed that the cytoplasm of the secretory cells contained homogeneously electron-dense granules at a young age, but two types of these granules could be recognized at 60 days old. In conclusion, this study provides a wide difference in the morphometric and the structure of the proventriculus from one day to 60 days old. This difference between the examined age-stages may be related to the feeding strategy (behavior) and the functional adaptations from the young to the older ages.

Influence of Liver Fibrosis on Lobular Zonation

Little is known about how liver fibrosis influences lobular zonation. To address this question, we used three mouse models of liver fibrosis, repeated CCl4 administration for 2, 6 and 12 months to induce pericentral damage, as well as bile duct ligation (21 days) and mdr2-/- mice to study periportal fibrosis. Analyses were performed by RNA-sequencing, immunostaining of zonated proteins and image analysis. RNA-sequencing demonstrated a significant enrichment of pericentral genes among genes downregulated by CCl4; vice versa, periportal genes were enriched among the upregulated genes. Immunostaining showed an almost complete loss of pericentral proteins, such as cytochrome P450 enzymes and glutamine synthetase, while periportal proteins, such as arginase 1 and CPS1 became expressed also in pericentral hepatocytes. This pattern of fibrosis-associated 'periportalization' was consistently observed in all three mouse models and led to complete resistance to hepatotoxic doses of acetaminophen (200 mg/kg). Characterization of the expression response identified the inflammatory pathways TGFβ, NFκB, TNFα, and transcription factors NFKb1, Stat1, Hif1a, Trp53, and Atf1 among those activated, while estrogen-associated pathways, Hnf4a and Hnf1a, were decreased. In conclusion, liver fibrosis leads to strong alterations of lobular zonation, where the pericentral region adopts periportal features. Beside adverse consequences, periportalization supports adaptation to repeated doses of hepatotoxic compounds.

Bile Microinfarcts in Cholestasis Are Initiated by Rupture of the Apical Hepatocyte Membrane and Cause Shunting of Bile to Sinusoidal Blood

Bile duct ligation (BDL) is an experimental procedure that mimics obstructive cholestatic disease. One of the early consequences of BDL in rodents is the appearance of so-called bile infarcts that correspond to Charcot-Gombault necrosis in human cholestasis. The mechanisms causing bile infarcts and their pathophysiological relevance are unclear. Therefore, intravital two photon-based imaging of BDL mice was performed with fluorescent bile salts (BS) and non-BS organic anion analogues. Key findings were followed up by matrix-assisted laser desorption ionization imaging, clinical chemistry, immunostaining, and gene expression analyses. In the acute phase, 1-3 days after BDL, BS concentrations in bile increased and single-cell bile microinfarcts occurred in dispersed hepatocytes throughout the liver caused by the rupture of the apical hepatocyte membrane. This rupture occurred after loss of mitochondrial membrane potential, followed by entry of bile, cell death, and a "domino effect" of further death events of neighboring hepatocytes. Bile infarcts provided a trans-epithelial shunt between bile canaliculi and sinusoids by which bile constituents leaked into blood. In the chronic phase, ≥21 days after BDL, uptake of BS tracers at the sinusoidal hepatocyte membrane was reduced. This contributes to elevated concentrations of BS in blood and decreased concentrations in the biliary tract. Conclusion: Bile microinfarcts occur in the acute phase after BDL in a limited number of dispersed hepatocytes followed by larger infarcts involving neighboring hepatocytes, and they allow leakage of bile from the BS-overloaded biliary tract into blood, thereby protecting the liver from BS toxicity; in the chronic phase after BDL, reduced sinusoidal BS uptake is a dominant protective factor, and the kidney contributes to the elimination of BS until cholemic nephropathy sets in.

Hair histology as a tool for forensic identification of some domestic animal species

Animal hair examination at a criminal scene may provide valuable information in forensic investigations. However, local reference databases for animal hair identification are rare. In the present study, we provide differential histological analysis of hair of some domestic animals in Upper Egypt. For this purpose, guard hair of large ruminants (buffalo, camel and cow), small ruminants (sheep and goat), equine (horse and donkey) and canine (dog and cat) were collected and comparative analysis was performed by light microscopy. Based on the hair cuticle scale pattern, type and diameter of the medulla, and the pigmentation, characteristic differential features of each animal species were identified. The cuticle scale pattern was imbricate in all tested animals except in donkey, in which coronal scales were identified. The cuticle scale margin type, shape and the distance in between were characteristic for each animal species. The hair medulla was continuous in most of the tested animal species with the exception of sheep, in which fragmental medulla was detected. The diameter of the hair medulla and the margins differ according to the animal species. Hair shaft pigmentation were not detected in all tested animals with the exception of camel and buffalo, in which granules and streak-like pigmentation were detected. In conclusion, the present study provides a first-step towards preparation of a complete local reference database for animal hair identification that can be used in forensic investigations.

Detection of occult right ventricular dysfunction in young Egyptians with type 1 diabetes mellitus by two-dimensional speckle tracking echocardiography

Background

Type 1 diabetes mellitus (T1DM) is a common chronic disorder of childhood and adolescence. T1DM induced cardiomyopathy has a different entity than T2DM as it relies on different pathophysiological mechanisms, and rarely coexists with hypertension and obesity. Evaluation of right ventricular (RV) function in diabetic patients has been neglected despite the important contribution of RV to the overall cardiac function that affects the course and prognosis of diabetic cardiomyopathy (DCM).

Objective

To assess RV myocardial performance in asymptomatic T1DM using speckle tracking and standard echo parameters and correlate it with functional capacity using treadmill stress test.

Patients and methods

Thirty-nine patients with TIDM (Group 1, mean age 18.2 ± 1.7y, BMI = 26.2 ± 3.9 kg/m²), without cardiac problems and 15 apparently healthy matched subjects as a control group (Group 2, mean age 18.8 ± 2.3 y, BMI = 22.8 ± 3.3 kg/m²) were enrolled. RV function was evaluated using conventional, tissue Doppler and 2D speckle tracking echocardiography (2D-STE). The peak RV global longitudinal strain (RV-GLS) was obtained. Functional capacity was assessed by treadmill exercise test and estimated in metabolic equivalent (METs).

Results

In this study; the diabetic group showed statistically highly significant decrease in the average RV-GLS (−14.0 ± 6.9 in group 1 vs. −22.7 ± 2.5 in group 2, P < 0.001), significant decrease in RV S velocity (9.5 ± 2.2 in group 1 vs. 11.5 ± 1.8 in group 2, P < 0.05), significantly reduced E/A ratio (1.0 ± 0.2 in group 1 vs. 1.1 ± 0.1 in group 2, P < 0.05), and highly significant increased E/Em ratio (7.9 ± 3.2 in group 1 vs. 5.2 ± 0.7 in group 2, P < 0.001). We did not found any significant differences between the two groups regarding the other echocardiographic or functional capacity parameters.

Conclusion

In asymptomatic patients with T1DM, in addition to RV diastolic dysfunction, early (subclinical) RV systolic dysfunction is preferentially observed with normal RV and left ventricular (LV) ejection fraction (EF). 2D-STE has the ability to detect subclinical RV systolic dysfunction.

Long bone development in the Japanese quail (Coturnix coturnixjaponica) embryos

The current study was undertaken to describe the main histological development stages of long bones (tibia and femur) from Japanese quail (Coturnix coturnix japonica) embryos. Whole Limbs or just tibia and femur of fifty Japanese quail embryos of different ages were fixed and embedded in paraffin or Spurr's resin. Paraffin and semi-thin, respectively, were undertaken and examined with light microscopy. Limb bud was established at day 5 of incubation. Mesenchymal cells differentiated into chondrocytes forming a cartilage template in the position of the future tibia and femur at day 6 of incubation. At day 7 of incubation, the cartilage template enlarged and had the shape and position of the future tibia and femur. At day 8, central chondrocytes underwent hypertrophy and were surrounded by a periosteal bone collar. Cellular and vascular invasion from the bone collar into the central zone of the cartilage template, cartilage resorption and formation of marrow tunnel and finally peripheral calcification was seen. Vascular cartilage canals penetrating the epiphysis were observed at day 9 and the canals gradually increased in thickness and number toward the hatching day. Articular epiphyseal growth cartilage with resting, proliferative and hypertrophic zones was clearly established by day 10 of incubation. After 17 days of incubation, the zonation of the articular epiphyseal cartilage were much clear, many cartilage canals were present within the epiphyses. In epiphyses of tibia but not femur, foci of chondrocytes hypertrophy were noticed close to the cartilage canals. The current study timed the main histological sequences of development of tibia and femur of embryonic quail.

Ossification of the femur and tibia of the post-hatching Japanese quail

The current study aimed to describe the histological changes of the femur and tibia of the post-hatching quail. Femur and tibia from 1-day- to 6-weeks post-hatching quail were processed for light microscopy. Histological examination revealed that endochondral ossification was a delayed process in the development of femur and tibia preceded by periosteal ossification. Femur and tibia of 1-day-post-hatching quail consisted of growth cartilage enclosed in a tube of periosteal bone collar. The collar extended toward the epiphysis dividing it into articular cartilage proper and lateral articular cartilage. Down to the articular cartilage, there was a physeal growth cartilage, in which the chondrocytes were organized into resting, proliferative and hypertrophic zones. Focal areas of hypertrophic chondrocytes were observed in the epiphysis of the tibia but not of the femur, which acted as a nidus for formation of the secondary ossification centre after in 2-week-posthathcing quail. Primary ossification centre was seen in both femur and tibia after 2 weeks and ossification continued replacing the cartilage until the 6th week when only permanent articular cartilage remained. Cartilage canals were present in both femur and tibia starting from the day 1, but chondrified and completely disappeared after the 6th week. The current study suggests that the periosteal ossification preceded the endochondral ossification and plays an important role in quail long bones development.

Morphological and histomorphological structure of testes of the catfish "Clarias gariepinus" from Egypt

Knowledge of the normal reproductive biology of catfish is of a great importance not only for better understanding of the theory of fish development, but also to be used as a baseline for understanding the pathological changes results form exposure to harmful toxicants. Thus, the aim of the current study was to elucidate the gross anatomical and light microscopic features of the testes of the catfish "Clarias gariepinus" from Egypt. The present study was carried out on 36 mature male catfish (Clarias gariepinus) collected monthly during the spawning period (April-September) throughout the Nile River, crossing Sohag city in Egypt, in the year 2011. Samples were processed for light and electron microscopy. Each testis consisted of two regions, a fringed outer lateral region and a smooth sagittal-medial region. Histological examination revealed that the testis was covered with a highly vascular connective tissue capsule sending septa dividing the testis into seminiferous lobules separated by interstitial connective tissue containing steroid secreting Leydig cells. Seminiferous lobules were made up of spermatogenic cells and Sertoli cells; the spermatogenic cells located within cysts formed by the cytoplasmic projections of the Sertoli cells. According to the maturation stages, the seminiferous lobules were classified into three types. Spermatogenic seminiferous lobules were lined with different spermatogenic cells but had few or no spermatozoa. Pubertal seminiferous lobules were packed with spermatozoa with few spermatogenic cells. Spent seminiferous lobules contained remnants of spermatozoa and spermatogenic cells. In conclusion, the testis of catfish Clarias gariepinus from Egypt was similar in structure to other catfish and teleost species.

Altered gene expression in early osteochondrosis lesions

Osteochondrosis is a condition involving defective endochondral ossification and retention of cartilage in subchondral bone. The pathophysiology of this condition is poorly characterized, but it has been proposed that the fundamental defect is failure of chondrocyte hypertrophy. The aim of the current study was to characterize phenotypic changes in chondrocytes associated with the initiation of osteochondrosis. Early lesions were induced in an equine model of osteochondrosis by feeding foals a high energy diet for 8 or 15 weeks. Lesions in articular-epiphyseal growth cartilage were examined histologically and by quantitative PCR analysis of expression of a number of genes representative of pathways that regulate chondrocyte behavior during endochondral ossification. There were more cells present in clusters in the lesions compared to normal articular cartilage. Expression of matrix metalloproteinase-13, type I collagen, type X collagen, and Runx2 mRNA was significantly greater in the lesions compared to normal cartilage from the same joint. Expression of vascular endothelial growth factor, type II collagen, connective tissue growth factor, aggrecan, Sox9, and fibroblast growth factor receptor 3 mRNA was not significantly different in lesions than in control cartilage. These observations suggest that osteochondrosis does not result from failure of chondrocytes to undergo hypertrophy.

Hypertrophy and physiological death of equine chondrocytes in vitro

REASON FOR PERFORMING STUDY

Equine osteochondrosis results from a failure of endochondral ossification during skeletal growth. Endochondral ossification involves chondrocyte proliferation, hypertrophy and death. Until recently no culture system was available to study these processes in equine chondrocytes.

OBJECTIVE

To optimise an in vitro model in which equine chondrocytes can be induced to undergo hypertrophy and physiological death as seen in vivo.

METHODS

Chondrocytes isolated from fetal or older (neonatal, growing and mature) horses were cultured as pellets in 10% fetal calf serum (FCS) or 10% horse serum (HS). The pellets were examined by light and electron microscopy. Total RNA was extracted from the pellets, and quantitative PCR carried out to investigate changes in expression of a number of genes regulating endochondral ossification.

RESULTS

Chondrocytes from fetal foals, grown as pellets, underwent hypertrophy and died by a process morphologically similar to that seen in vivo. Chondrocytes from horses age >5 months did not undergo hypertrophy in pellet culture. They formed intramembranous inclusion bodies and the cultures included cells of osteoblastic appearance. Pellets from neonatal foals cultured in FCS resembled pellets from older horses, however pellets grown in HS underwent hypertrophy but contained inclusion bodies. Chondrocytes from fetal foals formed a typical cartilage-like tissue grossly and histologically, and expressed the cartilage markers collagen type II and aggrecan mRNA. Expression of Sox9, collagen type II, Runx2, matrix metalloproteinase-13 and connective tissue growth factor mRNA increased at different times in culture. Expression of fibroblast growth factor receptor-3 and vascular endothelial growth factor mRNA decreased with time in culture.

CONCLUSIONS

Freshly isolated cells from fetal growth cartilage cultured as pellets provide optimal conditions for studying hypertrophy and death of equine chondrocytes.

POTENTIAL RELEVANCE

This culture system should greatly assist laboratory studies aimed at elucidating the pathogenesis of osteochondrosis.

Endochondral ossification: how cartilage is converted into bone in the developing skeleton

Endochondral ossification is the process by which the embryonic cartilaginous model of most bones contributes to longitudinal growth and is gradually replaced by bone. During endochondral ossification, chondrocytes proliferate, undergo hypertrophy and die; the cartilage extracellular matrix they construct is then invaded by blood vessels, osteoclasts, bone marrow cells and osteoblasts, the last of which deposit bone on remnants of cartilage matrix. The sequential changes in chondrocyte behaviour are tightly regulated by both systemic factors and locally secreted factors, which act on receptors to effect intracellular signalling and activation of chondrocyte-selective transcription factors. Systemic factors that regulate the behaviour of chondrocytes in growth cartilage include growth hormone and thyroid hormone, and the local secreted factors include Indian hedgehog, parathyroid hormone-related peptide, fibroblast growth factors and components of the cartilage extracellular matrix. Transcription factors that play critical roles in regulation of chondrocyte gene expression under the control of these extracellular factors include Runx2, Sox9 and MEF2C. The invasion of cartilage matrix by the ossification front is dependent on its resorption by members of the matrix metalloproteinase family, as well as the presence of blood vessels and bone-resorbing osteoclasts. This review, which places an emphasis on recent advances and current areas of debate, discusses the complex interactions between cell types and signalling pathways that govern endochondral ossification.

Physiological death of hypertrophic chondrocytes

OBJECTIVE

Post-proliferative chondrocytes in growth cartilage are present in two forms, light and dark cells. These cells undergo hypertrophy and die by a mechanism that is morphologically distinct from apoptosis, but has not been characterized. The aims of the current study were to document the ultrastructural appearance of dying hypertrophic chondrocytes, and to establish a culture system in which the mechanism of their death can be examined.

DESIGN

Growth cartilage from fetal and growing postnatal horses was examined by electron microscopy. Chondrocytes were isolated from epiphyseal cartilage from fetal horses and grown in pellet culture, then examined by light and electron microscopy, and quantitative polymerase chain reaction.

RESULTS

In tissue specimens, it was observed that dying dark chondrocytes underwent progressive extrusion of cytoplasm into the extracellular space, whereas light chondrocytes appeared to disintegrate within the cellular membrane. Pellets cultured in 0.1% fetal calf serum (FCS) contained dying light and dark chondrocytes similar to those seen in vivo. Transforming growth factor-beta1 or 10% FCS increased the proportion of dark cells and induced cell death. Triiodothyronine increased the differentiation of dark and light cells and induced their death. Dark cells were associated with higher levels of matrix metalloproteinase-13 expression than light cells, and light cells were associated with higher levels of type II collagen expression.

CONCLUSIONS

Light and dark hypertrophic chondrocytes each undergo a distinctive series of non-apoptotic morphological changes as they die. Pellet culture can be used as a model of the two forms of physiological death of hypertrophic chondrocytes.

Sex steroids in women with liver cirrhosis

Eighteen women with hepatic cirrhosis were examined for plasma levels of testosterone, estrone, estradiol, progesterone and sex hormone binding globulin. For eight who were amenorrheic, with advanced liver cirrhosis and ascites, the reduction of testosterone and rise in estrone and sex hormone binding globulin concentrations were significant. Plasma extradiol and progesterone were lower than normal levels, but the differences were not statistically significant. The other ten patients were menstruating (mostly irregularly), and their hormonal levels were assessed in different states of their cycles. All of them did not ovulate, had low levels of plasma progesterone and also showed consistent estrone concentration excess relative to estradiol and significant lowering of testosterone and elevation of sex hormone binding globulin. These findings are compared with previous reports on males with liver cirrhosis.