Days Of Fetal Age Research Articles

Gross Morphological and Scanning Electron Microscopic Study of Abomasum of Sheep (Ovis aries) during Pre-natal Life

Background: The enzymatic digestion occurs in the abomasum of sheep. A systematic comprehensive study on the embryogenesis of abomasums of sheep is lacking due to availability of sporadic information in current literature. So the current research was designed to explain the detail gross ontogenic occurrences along with scanning electron microscopic study of abomasum in sheep. Methods: From the local slaughter house, 12 healthy sheep foeti of non-descript breed were gathered and grouped into Group I (early pregnancy), Group II (mid pregnancy) and Group III (late pregnancy) having 04 foeti in every group. The abdomen of the foetus was incised and opened. The stomach was exposed and the gross observations were recorded. Then tissue samples from the abomasum were processed for scanning electron microscopic study. Result: The abomasums assumed comma shape at the gestational age of 32 to 48 days. At 67 days of foetus, the external constriction between fundus and pylorus of the abomasum was observed distinctly. In foeti of 32 to 48 days age, it was present between 13th rib and 1st lumbar vertebra. This topography changed to 8th rib and 3rd lumbar vertebra by 121 days of foetal age. The outline of the abomasal folds were noted first at 32 days of age. The height of the abomasal folds in fundus was larger than pylorus. The appearance of gastric pits on the mucosal surface was first observed at 63 days of gestation through scanning electron microscope.

A study of primary ossification centers in the hind limbs of Awasi sheep fetuses by double stains method and radiography.

Forty Local Awasi sheep fetuses were collected from several areas in Ninevah Governorate, further than local slaughterhouse. Their estimated ages calculated depending on crown-rump length with the aid of Richardson formula. The study aimed to detect the site and the time of appearance of ossification centers in the hind limb bones of Awasi sheep fetuses by using modified double staining method to demonstrate cartilage and bone , or by using radiography. The first ossification centers appeared in the hind limb bones was the primary center of the tibia and femur ,metatarsus with ilium then ischium at 45 , 46 , 48, 50-52 days of fetal age respectively. The ossification centers of pes phalanges appeared in the following sequence ; distal phalanx ,followed by the proximal phalanx and end by middle phalanx , at 58 ,60, 64 days respectively. Ossification centers of tarsal bones began to appear in calcaneus at 64 day , talus at 77 day , central & 4th tarsal bones at 96 day ,, followed by centers of 3rd & 2nd tarsal bones at 100 day while, the center of 1st tarsal bone appeared lastly at 105 day.Femur , tibia and metatarsus studied statistically by follow up the relative increase of their total lengths and length of their ossified part of diaphysis , the results show high significant variance in their growth and ossification of the three bones in first studied period (46-60 days) in comparison with the next sixth successive fortnightly periods

Similarities between bovine and human germline development revealed by single-cell RNA sequencing.

The germ cell lineage ensures the creation of new individuals and perpetuates the genetic information across generations. Primordial germ cells are pioneers of gametes and exist transiently during development until they differentiate into oogonia in females, or spermatogonia in males. Little is known about the molecular characteristics of primordial germ cells in cattle. By performing single-cell RNA-sequencing, quantitative real-time PCR, and immunofluorescence analyses of fetal gonads between 40 and 90 days of fetal age, we evaluated the molecular signatures of bovine germ cells at the initial stages of gonadal development. Our results indicate that at 50 days of fetal age, bovine primordial germ cells were in the early stages of development, expressing genes of early primordial germ cells, including transcriptional regulators of human germline specification (e.g. SOX17, TFAP2C, and PRDM1). Bovine and human primordial germ cells also share expression of KIT, EPCAM, ITGA6, and PDPN genes coding for membrane-bound proteins, and an asynchronous pattern of differentiation. Additionally, the expression of members of Notch, Nodal/Activin, and BMP signaling cascades in the bovine fetal ovary, suggests that these pathways are involved in the interaction between germ cells and their niche. Results of this study provide insights into the mechanisms involved in the development of bovine primordial germ cells and put in evidence similarities between the bovine and human germline.

Effects of low and high levels of maternal nutrition consumed for the entirety of gestation on the development of muscle, adipose tissue, bone, and the organs of Wagyu cattle fetuses.

This study aimed to investigate the effects of high and low levels of energy intake during the entire gestation period on the skeletal muscle development, organ development, and adipose tissue accumulation in fetuses of Wagyu (Japanese Black) cows, a breed with highly marbled beef. Cows were allocated to a high‐nutrition (n = 6) group (fed 120% of the nutritional requirement) or low‐nutrition (n = 6) group (fed 60% of the nutritional requirement). The cows were artificially inseminated with semen from the same sire, and the fetuses were removed by cesarean section at 260 ± 8.3 days of fetal age and slaughtered. The whole‐body, total muscle, adipose, and bone masses of the fetal half‐carcasses were significantly higher in the high‐nutrition group than the low‐nutrition group (p = 0.0018, 0.009, 0.0004, and 0.0362, respectively). Fifteen of 20 individual muscles, five of six fat depots, nine of 17 organs, and seven of 12 bones that were investigated had significantly higher masses in the high‐nutrition group than the low‐nutrition group. The crude components and amino acid composition of the longissimus muscle significantly differed between the low‐ and high‐nutrition groups. These data indicate that maternal nutrition during gestation has a marked effect on the muscle, bone, and adipose tissue development of Wagyu cattle fetuses.

Expression of high-mobility group box-Ⅰ and N-methyl-D-aspartate receptor in status epilepticus

Objective: To investigate the expression changes of high mobility group box-1 (HMGB1) and the 2B receptor of N- methyl -D- aspartate receptor (NR2B) in status epilepticus (SE). Methods: (1) Primary hippocampal neurons from SD rats with 16 to 18 days of fetal age were cultured in vitro for 7 days, and exposed to Mg(2+) free media for 3 hours. Those cultured neurons were randomly divided into control group and intermittent hypoxia group. (2) SD rats with similar weight were selected and randomly divided into control group and SE model group. The rat model with SE was established by an intraperitoneal injection of lithium chloride-piloearpine (LI-PILO). Real-time PCR technique was used to detect the expression of HMGB1 and NR2B mRNA. Results: In Sombati's cell model cultured in normal concentration of oxygen, the HMGB1 mRNA expression levels were 0.005 01±0.000 54, 0.026 76±0.003 75, 0.003 52±0.000 33, and the NR2B mRNA expression levels were 0.008 84±0.000 69, 0.012 23±0.000 90, 0.029 11±0.000 71, respectively, at 2, 4 and 6 h; compared with the expressions of HMGB1 and NR2B mRNA at the same time points of Sombatis cell model groups, the differences were also significant (all P<0.05). After the successful establishment of epilepsy model, the HMGB1 mRNA expression levels were 0.000 11±0.000 09, 0.000 18±0.000 01, 0.000 11±0.000 01, and the NR2B mRNA expression levels were 0.196 12±0.009 41, 0.232 11±0.006 27, 0.272 48±0.005 84, respectively, at 6, 8 and 10 h; compared with the expressions of HMGB1 and NR2B mRNA at the same time points of control groups, the differences were all significant (all P<0.05). Conclusion: HMGB1 mRNA expression levels increase at 2, 4 h, decrease at 6 h in the Sombati's cell model in normal oxygen culture, while increase at 6, 8 h, and decrease at 10 h in LI-PILO induced rat model with SE; the NR2B mRNA relative expression increases with time in both the Sombati's cell model in normal oxygen culture and rat model of SE.

Prenatal Development of the Lingual Intrinsic Skeletal Musculature, Lingual and Von Ebners Glands of the Tongue in Goat Foetii (Capra hircus)

The present study conducted on the tongue of 18 goat foetii revealed that the differentiation of skeletal muscle was first noticed among the mesenchymal cells at 40 days of foetal age (CRL = 3. 40 cm). These were better differentiated at 62 days of gestational age (CRL=10.0cm) and showed continued gradual development with advancing foetal age. The typical cross striations in the lingual intrinsic skeletal muscles was first observed at 121 days of foetal age (CRL = 27.50cm). The first appearance of lingual gland in the tongue of the goat foetii was observed at 62daysof gestation (CRL =10.10cm) and the first indication of appearance of Von-Ebner'sgland was observed in the tongue of goat foetii at 120 days (CRL= 31.1 cm).

Immunohistochemical Localization of Steroidogenic Enzymes in the Testis of the Sika Deer (Cervus nippon) During Developmental and Seasonal Changes

Testicular steroidogenesis and spermatogenesis during developmental and seasonal changes were investigated in male sika deer (Cervus nippon), a short-day seasonal breeder, to clarify the physiological mechanisms for reproductive function. The immunohistochemical localization of steroidogenic enzymes (P450scc, P450c17, 3betaHSD and P450arom), spermatogenesis and cell proliferation were analyzed in the testes of fetal (164 to 218 days of fetal age), fawn (0 years old), yearling (1 year old) and adult (more than 2 years old) male sika deer. Three kinds of steroidogenic enzymes, P450scc, P450c17 and 3betaHSD, essential for the synthesis of testosterone were located only in the Leydig cells of the testes from the fetal period, and these localizations did not change during developmental or seasonal stages. Immunoreactivity for P450arom, a key enzyme converting testosterone to estradiol, was also localized only in the Leydig cells of testes but was also further limited to the testes of yearlings and adults. Seminiferous tubules had already formed in the fetal testes examined in the present study. Spermatogenesis started in yearlings and was more active in the breeding season. In the adult sika deer testes, the Leydig cells, which displayed immunoreactivities for steroidogenic enzymes, changed to have more cytoplasm in the breeding season than in the non-breeding season. Cell proliferation of Leydig cells was hardly observed in adult testes during seasonal changes. The present results suggested that sika deer testes start to synthesize testosterone from the fetal period, that seasonal changes in testosterone and estradiol syntheses are dependent on the quantitative variation of steroidogenic enzymes synchronized with the size of Leydig cells and that estradiol synthesized in yearling and adult testes makes a contribution to the initiation and recrudescence of spermatogenesis and spermiogenesis in the sika deer.

Different mechanisms operating during different critical time-windows reduce rat fetal beta cell mass due to a maternal low-protein or low-energy diet

Adverse events during intra-uterine life may programme organ growth and favour disease later in life. In animals, protein or energy restriction during gestation alters the development of the endocrine pancreas, even though the duration of malnutrition is different. Here, we evaluate the specific effects of both diets during different periods of gestation and the mechanisms underlying the decreased beta cell mass. Pregnant Wistar rats were fed either a low-protein or a low-energy diet during the last week of gestation or throughout gestation. Fetuses and their pancreases were analysed at days 15 and 21 of gestation. The low-energy diet reduced the beta cell mass from 21-day-old fetuses by 33 or 56% when administered during the last week or throughout gestation, respectively. Fetal corticosterone levels were increased. At 15 days of fetal age, the number of cells producing neurogenin 3 (NEUROG3) or pancreatic and duodenal homeobox gene 1 (PDX-1) was reduced. Neither islet vascularisation nor beta cell proliferation was affected. The low-protein diet, in contrast, was more efficient in decreasing the fetal beta cell mass when given during the last week of gestation (-53%) rather than throughout gestation (-33%). Beta cell proliferation was decreased by 50% by the low-protein diet, independently of its duration, and islet vascularisation was reduced. This diet did not affect NEUROG3- or PDX-1-positive cell numbers. Although both diets reduced the fetal beta cell mass, the cellular mechanisms and the sensitivity windows were different. Early alteration of neogenesis due to elevated corticosterone levels is likely to be responsible for the decreased beta cell mass in low-energy fetuses, whereas impaired beta cell proliferation and islet vascularisation at later stages are implicated in low-protein fetuses.

Electron microscopic findings in a case of fatal human measles pneumonia

The patient, a 9-month-old male infant, was born at 37 weeks and 3 days of fetal age. At 2 months before his death, the patient was found to have measles pneumonia, as a high titer of antimeasles virus antibody was demonstrated by the ELISA method. This case of interstitial pneumonia was caused by the measles virus, with intracytoplasmic inclusion bodies in giant cells and type II alveolar cells in alveolar and bronchiolar spaces, with rare intra-nuclear inclusion bodies. The inclusion bodies indicated a positive response on immunohistochemical reaction using antimeasles polyclonal and antimeasles monoclonal antibodies. Electron microscopic and immunoelectron microscopic studies revealed that the inclusion bodies were composed of electron-dense filamentous or amorphous substances and rod-shaped materials with a microtubular structure 15–20 nm in diameter that stained intensely with immunogold particles.

Developmental Control of Cathepsin B Expression in Bovine Fetal Muscles

Expression of lysosomal cysteine proteinases was studied during fetal calf muscle development. The peptide cleaving activities of cathepsins B and L decreased strongly from 80 to 250 days of fetal age. This decrease in cathepsin activities occurred similarly in three muscles exhibiting different metabolic and contractile properties in adult animals. Cathepsin B from adult or fetal muscle revealed similar enzymatic properties, but presented a five- to sixfold lower concentration in adult muscle as indicated by active-site titration withl-3-carboxy-trans-2,3-epoxypropionyl-leucylamido-(4-guanidino)butane. During fetal growth, decreases in muscle cathepsin B specific activity and active enzyme concentration were associated with a parallel drop of cathepsin B mRNA levels. Bovine cathepsin B is encoded by two different transcripts resulting from alternative polyadenylation [Mordier, S.B., Béchet, D. M., Roux, M. P., Obled, A., and Ferrara, M. (1995)Eur. J. Biochem.229, 35–44]. As revealed by ribonuclease protection assays, the two mRNAs encoding cathepsin B declined similarly during fetal muscle growth. This study indicates that lysosomal proteinases in skeletal muscle are under developmental control. The decrease of muscle cathepsins during fetal development appears sufficient to account for the low levels of these enzymes in adult muscles. In fetuses, high activities of lysosomal cysteine proteinases might be important for remodeling muscles during early development.

A Morphometric Study of Interstitial Cells in Equine Fetal Gonads

A morphometric study of gonadal interstitial cells in 16 equine fetuses, ranging in age from 120 to 330 days of fetal age, was done to assess the possible relationship of fetal gonads to high plasma concentrations of immunoreactive inhibin in pregnant mares during the second half of pregnancy with its peak at about 280 days of gestation, which has been reported recently. Interstitial cells of fetal gonads underwent progressive hypertrophy to reach a maximum size around 250 days of gestation, and subsequent degenerative changes in these cells resulted in a rapid decrease in the volume density and size of the interstitial cells. Thus, the morphometric change in the interstitial cells was almost synchronous with high concentrations of immunoreactive inhibin in the plasma of pregnant mares. This observation, taken in conjunction with the fact that inhibin α-chain (1-30) was detected immunohistochemically in the cytoplasm of the interstitial cells, appears to provide morphometric evidence that the interstitial cells in fetal gonads are closely related to inhibin production.

Development of Prolactin and Growth Hormone Production in the Fetal Rat Pituitary: An Immunochemical Study: (hormone production/ontogeny/fetal rat pituitary/immunochemistry).

Western immunoblot analysis was performed to monitor contents of prolactin (PRL), growth hormone (GH) and Pit-1, a transcription factor required for both GH and PRL gene expression, in developing fetal rat pituitaries. Both PRL and GH were first detected in pituitary extracts at 18 days of fetal age and their contents increased during the rest of the fetal period. Pit-1 was detectable from 16 days on. Quantitative densitometry scanning analysis of Western immunoblots showed that the PRL and GH contents were less than 10 ng per pituitary at 18 days. The PRL content increased to about 19 ng at 21 days (the last day of gestation), whereas the GH content showed much larger increase in the same period to reach about 1.2 μg per pituitary. In primary culture, dispersed pituitary cells from 19 day-old fetuses incorporated [35 S]-amino acids into immunoprecipitable GH. The incorporation into PRL was detectable after stimulation with 1 nM 17β-estradiol. These results suggests that the rat pituitary starts to produce both PRL and GH at around 18 days of fetal age.

Immunohistochemical Studies on Ontogeny of Bovine Lymphoid Tissues.

Developing lymphoid tissues of bovine fetuses ranging from 70 to 270 days of fetal age were examined by histological and immunohistochemical procedures. In the peripheral blood, surface membrane immunoglobulin bearing cells (B-lymphocytes) and sheep red blood cell rosette forming cells (T-lymphocytes) had already appeared by 70 days of fetal age. In the lymph nodes intracytoplasmic IgM positive cells appeared at 90 days of fetal age. The cells positive for IgG appeared at 150 days of fetal age and IgA positive cells appeared at 180 days of fetal age. The spleen contained intracytoplasmic immunoglobulin positive cells at almost the same time as those in the lymph nodes. In the ileocecal region, IgM positive cells and IgG positive cells were present at 180 days of fetal age and IgA positive cells were present at 210 days of fetal age. The tonsils contained IgM positive cells and IgG positive cells at 240 days of fetal age. In the thymus, terminal deoxynucleotidyl transferase positive cells appeared at 90 days of fetal age.

The developmental anatomy of the equine navicular bursa and associated structures.

The navicular bone, navicular bursa and their associated structures were collected from 20 horses ranging in age from 80 days gestation to 2 years post-gestation. The right front foot of every horse was sampled for light microscopy. The development of the navicular bursa and associated structures were studied. Study of the developmental anatomy of the equine navicular bursa established that the bursa is a distinct entity in both the fetus and the adult horse. Development of the bursal cavity in the fetus was found to be complete by 120 days of gestation. Synovial membrane of the navicular bursa was first evident at 100 days of fetal age. With increasing fetal maturation there was a concurrent development in the synovial membrane consisting of increased cellularity, vascularity and villi formation. Nerve fibers or nerve endings were not observed within the synovial membrane of the navicular bursa. However, nerve bundles were often observed within the associated connective tissue, bursal capsule and distal navicular ligament. Pacinian corpuscles were observed in the 200-day fetus in close proximity to the navicular bursa. The development of a fibrous bursal capsule was first evident at 160 days fetal age, thereafter increasing in both thickness and density. Ligaments of the navicular bone were found to develop early in fetal life. At 100 days the collateral sesamoidean ligaments were well developed; however earliest evidence of formation of the distal navicular ligament was at 120 days. In both the fetus and the adult the proximal blood supply to the navicular bone was found to course dorsally in close proximity to the collateral sesamoidean ligament to enter the proximal border of the navicular bone. Concurrent with weight bearing there was a dorsal palmar orientation of the bone trabeculae of the navicular bone. In the young postgestational horses a progressive roughening or fraying of the palmar surface of the navicular bone and the apposing surface of the deep digital flexor tendon was evident.

A morphometric study of foetal and newborn cardiac growth in the horse.

A morphometric study of hearts in 81 equine foetuses, ranging in age from 190 to 330 days of foetal age, and in 26 newborn foals is reported. The mean weight, external dimensions, ventricular wall thickness and circumference of the atrio-ventricular orifice were measured. Features of the main associated vessels of the heart were also recorded. All cardiac measurements of foetuses increased linearly throughout the latter half of pregnancy and were highly correlated with foetal age. This linear growth pattern was also found in the parameters of the associated arterial trunks. The ratio of the right ventricular weight to the total ventricular weight in the equine foetuses increased gradually from 0.27 (Day 190) to 0.34 (full term), but in newborn foals, this ratio began to decrease soon after birth, declining from 0.32 to 0.28 by 11 days of age. The interventricular septum was thickest followed by the right ventricular wall, and the left ventricular wall was thinnest during the period of gestation studied. The right ventricle was 3.2 per cent to 31.5 per cent thicker than the left ventricle.

The development of mast cells in facial skin, palate and tongue of the mouse

This was examined in connective tissues of facial skin, palatal mucosa and tongue in fetal and adult mice. Mast cells were first observed in skin at 15 days of fetal age, but not until 17 days in palate and tongue. With increasing age they increased in size and granularity. At birth they were 6–7 times more numerous per unit volume of tissue in skin compared with palate or tongue but, in the adult, numbers were similar in each region. Either mast cells enter developing tissues at different times or they differentiate and proliferate in some regions before they do so in others.

Carbonic anhydrase activity in the blood of adult sheep, fetal sheep and lambs

1. 1. The activity of carbonic anhydrase (E.C.4.2.1.1) (CA) has been measured in the blood of adult and fetal sheep and lambs. 2. 2. The mean activity in adult sheep was 0.89 enzyme units (EU) per 100 μg of Hb. 3. 3. The activity in fetal sheep aged 90 days was just below 20% of this and in fetuses near full term was just under 40% of the mean adult level. The regression line gave an increase of CA activity (per 100 μg Hb) of 0.004 EU/day. 4. 4. The appearance of CA in fetal blood normally occurred before any detectable production of adult Hb. 5. 5. One aberrant fetus showed early development of the adult pattern in the red cells, having adult type Hb and adult levels of CA during the period of 116–128 days of fetal age. 6. 6. In the period after birth the CA level in the blood rose rapidly, reaching the adult level 30 days after birth. During this period activity per 100 μg Hb increased by 0.014 EU/day, significantly faster than during fetal life.

The early ontogenesis of thyroid hormone receptor in the rat fetus.

We have determined the concentration of thyroid hormone receptor binding sites in nuclear extracts derived from rat fetal organs throughout gestation and the postnatal period. Before day 14 of gestation nuclear extracts were obtained from whole fetuses. No receptor binding activity could be detected at day 12 of gestational age, and small amounts were detected at day 13 (maximum binding capacity less than 50 fmol/mg DNA). The receptor could be measured in pools of individual organs from day 14 (brain) or from day 16 (heart, liver, and lung) onwards. The order of analog binding affinity at 14 days was triiodothyroacetic acid = T3 greater than T4 greater than rT3, suggesting that at 14 days of fetal age the receptor has the same binding specificity as the receptor from mature tissues. In brain, the concentration of binding sites increased from 77 fmol/mg DNA at 14 days to 210 fmol/mg DNA at 17 days, remaining at this level until birth. Receptor concentration was identical whether the binding assays were performed on purified nuclei or nuclear extracts. There was no effect of maternofetal hypothyroidism on receptor concentration in the brain at 21 days of gestational age. Lung concentrations of receptor also remained constant during the fetal period. During the postnatal period, there was an increase in receptor concentration in brain and lung, with maximum levels at day 6. The pattern of receptor development in heart and liver was different, since its concentration increased progressively throughout the fetal and postnatal periods towards the levels found in adult rat tissues. The results suggest that the appearance of the thyroid hormone receptor coincides with that of the first fetal thyroid gland structures, but that it occurs much before thyroid function is fully established. As far as the receptor is concerned, fetal tissues have the potential to respond to thyroid hormone as early as the 13th day of gestational age.

The placental transfer of IgG in the cynomolgus monkey.

The placental transfer of IgG from the mother to her fetus was investigated with colony-bred cynomolgus monkeys. Very low levels of IgG were detected in sera of 84 days old fetus, indicating that transplacental transfer of IgG had started by this fetal age. Afterwards, gradual increase in the IgG level continued till 140 days of fetal age. A marked increase in the level was noted after 140 days of fetal age, during the last 4 weeks of full gestation term. Fetal anti-measles antibody increased in a pattern similar to that in the IgG level. The IgG level and anti-measles and anti-streptolysin O antibody titers of newborns never exceeded those of their mothers.

Cartilage response to plasma and plasma somatomedin activity in rats related to growth before and after birth.

Cartilage response to plasma, plasma somatomedin activity, body weight and length were measured in rats from 15 days of fetal age to 37 days postnatally. The metabolic activity of costal cartilage was assessed by the incorporation of [35S]sulphate in basal medium and after stimulation by plasma. It was found that (a) A significant stimulation of isotope uptake above basal levels occurred in the presence of 15% standard adult rat plasma at every age studied. (b) The degree of stimulation, a measure of cartilage sensitivity to plasma growth factors, increased through the latter part of fetal life but fell after birth. A high degree of cartilage stimulation was seen on day 6 of postnatal life. (c) The changes in cartilage sensitivity and in the stimulated isotope uptake, resembled the changes observed in growth rate for body weight, nose-rump length and tail length. (d) Plasma somatomedin activity measured by the pig costal cartilage assay was low in the fetus and neonate but rose to adult values 9 days after birth. However, plasma from fetal or neonatal rats tested on cartilage from rats of the same age was equipotent to adult rat plasma. (e) Plasma from hypophysectomized adult rats had a low potency in stimulating isotope uptake by neonatal rat cartilage but was equipotent to normal adult rat plasma in its action on fetal cartilage. (f) The action of plasma from hypophysectomized rats on fetal cartilage was unaffected by dialysis but was destroyed by incubation with trypsin.