Effects of amnio-allantoic fluid exchange on bowel contractility in chick embryos with gastroschisis

Background/Purpose: Intestinal damage in patients with gastroschisis is characterized by bowel wall thickening, intestinal dilatation, mesenteric shortening, and a fibrous peel. The prevention of intestinal damage in gastroschisis by amnio-allantoic fluid (AAF) exchange has been reported using histologic and macroscopic evaluation of intestines, but the effects of this treatment on bowel contractility have not been investigated. The current study was performed to determine the effect of AAF exchange on the intestinal contractility in chick embryos with gastroschisis. Methods: Thirteen-day-old fertilized chick eggs were used. Gastroschisis was created through amnio-allantoic cavity. There were 3 study groups: control group, gastroschisis-only group, and gastroschisis-plus-exchange group. The bowels were evaluated by an in vitro muscle strip technique, and the response was expressed as a percentage of the maximum acetylcholine evoked contraction (E_max) in each tissue obtained. Additionally, parasympathetic ganglion cells per 10 plexus at the intestinal wall were counted. Differences between groups were analyzed by analysis of variance (ANOVA) followed by Tukey-Kramer. Probabilities of less than 5% were considered significant. Results: The intestines were thickened and covered by fibrous peel in the gastroschisis-only group when compared with the control group and the gastroschisis exchange group morphologically. There was a statistically significant decrease in contractility in the gastroschisis-only group compared with the control group (P [lt ] .05). It exerted 42.03 [plusmn] 46.73% contraction of control group's E_max. This decrease in contractility was significantly reversed in the exchange group (P [lt ] .05; E_max value of gastroschisis plus exchange group was 71.45 [plusmn] 23.54% of control group's E_max). Although the number of ganglia per 10 plexus was 76.7 [plusmn] 4.3 in the control group, it was measured 28% less in the gastroschisis-only group (P [lt ] .05). There was no significant difference between the ganglion numbers of control and exchange groups. Conclusions: Prenatal AAF exchange treatment prevents decreased bowel contractility in gastroschisis. Gastroschisis does not affect intestinal ganglia morphology, but the number of ganglion cells decreases. AAF exchange prevents these functional and morphologic adverse effects of disease. By these findings the expectancy of a better clinical result in gastroschisis with intrauterine pretreatment by amniotic fluid exchange increases.     

The effects of intraamniotic human neonatal urine and meconium on the intestines of the chick embryo with gastroschisis

BACKGROUND/PURPOSE: Urinary waste products in the amniotic fluid has been implicated as a cause of intestinal damage (ID) in gastroschisis based on the fact that fetus urinates physiologically into the amniotic cavity. However, experimental and clinical data suggest that intrauterine defecation is a physiological event, thus gastrointestinal waste products also may be responsible for ID in gastroschisis. An experimental study was performed to investigate the effects of intraamniotic human neonatal urine and diluted meconium on the intestines of chick embryo with gastroschisis. METHODS: Five-day-old fertilized chick eggs (Gallus domesticus) were used. Gastroschisis was created through amniotic cavity without opening the allantoic cavity. Sterile urine and meconium were obtained from newborn humans, and 1% meconium suspension was prepared. The eggs were divided in to 3 groups. In the first group, gastroschisis was created, and amniotic fluid was reinstilled without changing its composition (control group). Equal amounts of amniotic fluid and urine mixture was instilled into the amniotic cavity in second group (urine group) and 1% meconium suspension was instilled in similar fashion in the third group after creation of gastroschisis (meconium group). RESULTS: Histopathologic features of the intestines of the urine group did not differ from the intestines of the control group. The meconium group's bowel showed serosal thickening, inflammation, focal fibrin, and collagen deposits. Histopathologic changes of intestines induced by intraamniotic diluted meconium are consistent with the ones described for human gastroschisis specimens. CONCLUSION: Gastrointestinal waste products seem responsible for the ID in gastroschisis rather than urinary waste products.     

Morphologic study of the intestine in an experimental model of amnioinfusion in fetal rabbits with gastroschisis

An experimental model of serial amnioinfusion has been developed in fetal rabbits with gastroschisis, using an intraamniotic catheter connected to a subcutaneous port. Fetuses of 4 groups were compared 7 days after surgery: group A: gastroschisis and daily amnioinfusion through an implanted catheter; group C: gastroschisis and blind amniotic catheter; group G: gastroschisis without catheter; group O: nonoperated fetuses. Survival rate, fetal body weight, lung weight, intestinal weight and length were determined. Computer aided morphometric analysis was performed, in which intestinal diameter, thickness and villi length were measured. Amniotic fluid samples were recovered along the experimental period. Intestinal length was significantly shorter and had a significantly thicker wall than nonoperated fetuses; we found no other morphometric differences between gastroschisis treated with amnioinfusion (group A) and the other gastroschisis groups (C and G). Amnioinfusion did not affect fetal survival rate; the amniotic catheter alone did not cause pulmonary hypoplasia due to significant amniotic leak. The physiological decrease in amniotic volume towards the end of gestation has not been modified by this regime of amnioinfusion.     

The effect of gastroschisis on experimental diaphragmatic hernia in fetal rabbits

Purpose

In this study, the authors analyzed the effect of experimentally induced gastroschisis on pulmonary hypoplasia in fetal rabbits with congenital diaphragmatic hernia (CDH).

Methods

Twenty-three pregnant rabbits underwent fetal surgery on gestational day 24 through 27. A left diaphragmatic hernia was created in 1 fetus (DH group) from each rabbit, and a left diaphragmatic hernia with gastroschisis was created in another fetus (GS group). The fetuses were delivered on gestational day 27 through 33. Histologic and morphometric examination of the lungs in each group was done.

Results

In the DH group, the lungs were hypoplastic with a decrease in lung weight to body weight ratio and an increase pulmonary arterial medial wall thickness. The alveolar septae were markedly thickened with increased interstitial tissue and diminished alveolar air spaces. In the GS group, the alveolar septae were thickened but narrower than those of DH group, and air spaces were increased. The pulmonary arterial wall was markedly thickened in the DH group but only slightly thickened in the GS group.

Conclusions

Pulmonary hypoplasia seen in newborn rabbits after experimentally induced diaphragmatic hernia is less severe in those rabbits with both gastroschisis and DH.     

The effect of chick embryo hyperflexion on tracheoesophageal development

Chick embryos were hyperflexed by placement of a ligature at two critical stages in the development of the foregut, in order to test the theory that esophageal atresia and tracheoesophageal fistula result from embryonic hyperflexion. Only one "H-type" tracheoesophageal fistula was found. There were no significant disturbances of either tracheal or esophageal growth.     

血管内皮生长因子单克隆抗体治疗子宫内膜异位症的实验研究

目的：观察血管内皮生长因子（VEGF）单克隆抗体（单抗）对子宫内膜异位症（EMs）血管生成的抑制作用,为从抗血管途径治疗EMs提供依据。方法：60只新鲜受精鸡蛋随机分为接种组（20枚）、接种治疗组（20枚）、单纯空白组（10枚）和空白载体组（10枚）。接种组和接种治疗组建立子宫内膜异位症鸡胚绒毛尿囊膜（CAM）模型,接种治疗组给予VEGF单抗10μg/d。单纯空白组不接种子宫内膜,空白载体组以无菌明胶海绵为载体,给予PBS20μg/d。通过显微血管计数、原位铺片及组织学观察等方法检测接种的子宫内膜组织对CAM血管生成和VEGF单抗对异位内膜病灶生长行为的影响。结果：接种组CAM血管生成反应明显增强,血管数目显著高于单纯空白组和空白载体组;接种治疗组血管数目显著低于接种组,有明显的间质坏死。结论：子宫内膜能明显促进CAM的血管生成,VEGF单抗能够显著抑制异位病灶的血管形成,并抑制子宫内膜的生长,证实抗血管途径可以作为治疗EMs的一种有效方法。     

人胃癌鸡胚移植模型的建立及其肿瘤生物学研究

目的　建立人胃癌鸡胚移植模型 ,为胃癌研究提供一种简便实用的手段。方法　将人胃癌细胞系SGC 790 1细胞接种到鸡胚绒毛尿囊膜 (CAM)上 ,动态观察移植瘤的形态学及肿瘤生物学特性 ,分析影响移植瘤成活的因素 ,并对瘤组织行组织学检查。结果　成功建立了人胃癌鸡胚移植模型 ,移植瘤组织学结构与人胃癌相似 ;接种癌细胞数量影响接种成瘤率 ,癌细胞数量越大 ,成瘤率越高 ;移植瘤可诱发大量血管生成并向肿瘤呈放射状集中。结论　将SGC 790 1细胞接种到鸡胚上建立鸡胚移植胃癌是可行的 ,本模型可动态观察胃癌生长 ,模拟其在体内生长情况 ,为胃癌研究提供一种简便实用的手段     

The effect of polymethylmethacrylate on bone: an experimental study

Summary In order to assess the response of bone to low-viscosity polymethylmethacrylate, CMW or Simplex acrylic cement was digitally packed while in a doughy state into drill holes in the proximal diaphysis in each of four long bones (humeri and tibiae) of mongrel dogs. Histological assessment was performed in areas of minimal load at the interface between the viscoelastic bone and the acrylic cement. Decalcified and undecalcified sections were evaluated and a remodeling or activity index calculated. Fluorescent labeling studies were performed in order to assess bone growth. Animals were killed at 2, 4, or 5 months. Histological analysis showed a thin connective-tissue membrane containing scattered giant cells and histiocytes at the bone-cement interface. Inflammation was not an important facet of this response. The marrow and trabecular bone were viable, except for scattered localized areas of marrow necrosis and fibrosis immediately adjacent to the cement. The bone adjacent to the cement showed a lower remodeling or activity index, fewer fluorescent bands, and smaller distances between successive bands, suggesting decreased bone formation and turnover. The etiology of these findings may include vascular disturbance secondary to disruption of the cortical and marrow circulation, temperature effects during cement polymerization, and/or chemical effects from the acrylic monomer.     

The effect of polymethylmethacrylate on bone: an experimental study

In order to assess the response of bone to low-viscosity polymethylmethacrylate, CMW or Simplex acrylic cement was digitally packed while in a doughy state into drill holes in the proximal diaphysis in each of four long bones (humeri and tibiae) of mongrel dogs. Histological assessment was performed in areas of minimal load at the interface between the viscoelastic bone and the acrylic cement. Decalcified and undecalcified sections were evaluated and a remodeling or activity index calculated. Fluorescent labeling studies were performed in order to assess bone growth. Animals were killed at 2, 4 or 5 months. Histological analysis showed a thin connective-tissue membrane containing scattered giant cells and histiocytes at the bone-cement interface. Inflammation was not an important facet of this response. The marrow and trabecular bone were viable, except for scattered localized areas of marrow necrosis and fibrosis immediately adjacent to the cement. The bone adjacent to the cement showed a lower remodeling or activity index, fewer fluorescent bands, and smaller distances between successive bands, suggesting decreased bone formation and turnover. The etiology of these findings may include a vascular disturbance secondary to disruption of the cortical and marrow circulation, temperature effects during cement polymerization, and/or chemical effects from the acrylic monomer.     

Amniotic fluid ferritin as a marker of intestinal damage in gastroschisis: a time course experimental study

Background/Purpose

Intestinal damage (ID) is closely related to morbidity and mortality in gastroschisis. This study was performed to determine the intraamniotic substances that may correlate ID and also to verify their time course levels that would be useful for determining when ID starts in gastroschisis.

Methods

In this study, 13-day-old fertilized chick eggs were used. The amnioallantoic membrane was perforated to create amnioallantoic cavity in all embryos. Gastroschisis was created in gastroschisis group to simulate human gastroschisis. Amnioallantoic fluid samples were collected from the embryos on the 13th to 19th gestational days, and the intestines of each group were harvested for evaluation. Amnioallantoic levels of interleukin-8, ferritin, alkaline phosphatase, and amylase were measured. Serosal thickness of the intestines in each group was evaluated.

Results

Increasing amnioallantoic fluid levels of interleukin-8, alkaline phosphatase, and amylase were found in both groups. In contrast to control group, ferritin levels, as a sign of inflammation, were found increased only in gastroschisis group. Histopathologic examination of intestines in the gastroschisis group showed a significant increase in the serosal thickness especially after the 16th day.

Conclusion

Increases in amnioallantoic fluid levels of ferritin show promise as a marker for determining ID encountered in gastroschisis but warrant further investigation.     

Mucosal morphology in experimental intestinal atresia: studies in the chick embryo

Lesions identical to those observed in human intestinal atresia (IA) have been experimentally reproduced in several mammal models by either mesenteric vessels or intestinal wall injury. The recent availability of an avian model led us to investigate whether the same lesions could be studied at less expense. An intestinal loop within the body stalk hernia was coagulated on the 12th incubation day in 427 chick embryos (group 3), the lesions were studied in survivors 4 days later under light and scanning electronmicroscopy (EM), and the findings were compared with those in 12 control embryos (group 1) and 14 sham-operated ones (group 2). Types I or II atresias were obtained in 61 (73.4%) of the 83 survivors in group 3. Seromuscular layers were normal at both ends of the lesion; there was some flattening of villi at the proximal, dilated end, and hyperplasia with apparently lengthened, branched villi at the distal, unused one. Mucosal pattern under light microscopy was strikingly close to that observed in human IA and in the fetal lamb experimental model. On the other hand, scanning EM showed that in this model there were no villi as such, but rather prominent mucosal folds that were regularly arranged in a tire-rubber pattern in the normal intestine, flattened and distended in the dilated one, and again roughly normal in the distal unused gut. High-power magnification scanning EM showed that enterocytes were normal at all levels but, in agreement with previous findings in the fetal lamb model, that intercellular spaces were widened in the dilated portion adjacent to the obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)     

The nutrition of the fetus with intestinal atresia: studies in the chick embryo model.

This article examines the effects of experimental prenatal intestinal obstruction on the growth and blood composition of chick embryos. Intestinal atresia (IA) was produced by bipolar bowel electrocoagulation in fertile eggs on the 14th day of incubation. The chicks killed on the 19th day were measured, weighed, and blood-sampled. Twenty-three control, 10 sham-operated, and 11 IA chicks were studied. Animals with IA were severely undernourished by weight (43.4 +/- 4.7 v 70.3 +/- 7.6% of egg weight, P < .001) and length (15.3 +/- 1.1 v 18.1 +/- 0.9 mm tibial length, P < .001) in comparison with sham-operated ones. Their hematocrit was slightly lower, and total protein increased. Prealbumin was absent in their sera and albumin, alpha and beta globulins were significantly decreased, whereas gamma-globulin was greatly increased. Sodium, potassium chloride, urea, and glucose remained within normal limits. The lack of placenta in the avian embryo precludes any supply of nutrients by this route and the ingestion of amniotic fluid, which is protein-rich after the 13th day of incubation, when the opening of the seroamniotic connection allows albumen to be mixed with it, becomes the main source of nutrients until hatching. Obstruction of the main incoming avenue by IA induces severe malnutrition in this model which relies on this route to a greater extent than the human fetus. In spite of the obvious biological differences between the avian embryo and the human fetus, the present evidence supports the hypothesis that prenatal interruption of the amniotic fluid transit contributes to fetal undergrowth in IA.     

The effect of ultrasound on flap survival: an experimental study in rats

BACKGROUND: Ultrasound is commonly used by physical therapists, but there is no consensus regarding the most effective therapeutic dose for accelerating healing of open or closed wounds. Now, the effect of therapeutic ultrasound on the formation of new blood vessels in full-thickness excised lesions in the flank skin of adult rats has been assessed quantitatively using microfocal X-ray techniques. METHODS: To investigate this, 30 rats were divided into three groups of 10 animals: a control group and two treated with ultrasound groups. Random dorsal skin flaps were elevated on the rats. In the control group, no operative procedures agents were used. Of the two treated groups, group 1 were exposed to pulsed ultrasound (2 ms on, 8 ms off) at an intensity of 0.1 W cm(-2) SATA (frequency either 0.75 MHz or 3.0 MHz). Group 2 exposed to pulsed ultrasound (2 ms on, 8 ms off) at an intensity of 0.18 W cm(-2) SATA (frequency either 0.75 MHz or 3.0 MHz), respectively. RESULTS: The areas of flap necrosis were measured in each group. The median lengths of flap necrosis of the groups were 79.3, 57.0, and 35.3 mm, respectively. There was a statistically significant improvement of flap necrosis in ultrasound-treated groups compared with the control group (group 2, p=0.001; group 3, p=0.001). Furthermore, there was less necrosis in the high intensity ultrasound-treated group than the low intensity-treated group. CONCLUSION: Ultrasound may have an intensity-dependent effect to increase flap survival in random skin flaps.     

An improved model of experimental gastroschisis in fetal rabbits.

Previous animal models of gastroschisis have been associated with high mortality and variable degrees of intestinal evisceration. Using current fetal surgical techniques, an improved model of gastroschisis in fetal rabbits was developed. Twenty-eight time-mated New Zealand white rabbits underwent hysterotomies and fetal exposure on gestational day 25 (33-day gestation). Control fetuses (C) underwent fetal manipulation only. Gastroschisis fetuses (GS) had creation of right midabdominal wall defects. Twenty-five of 28 does (89%), 9 of 13 C fetuses (69%), and 18 of 22 GS fetuses (82%) survived. At the time of cesarean delivery 5 days later, GS fetuses had significantly lower body weights, intestinal lengths, and mucosa/submucosa height ratios (a measure of bowel wall edema), and significantly greater intestinal densities when compared with C fetuses (P less than .05, t test). This study demonstrates that (1) gastroschisis abdominal wall defects can be created in fetal rabbits with high survival rates; (2) experimental gastroschisis is associated with a profound decrease in fetal weight; and (3) eviscerated intestine is heavier, shorter, and thickened compared with normal control intestine, mimicking the clinical situation.     

The effect of hyaluronan combined with microfracture on the treatment of chondral defects: an experimental study in a rabbit model

Because articular hyaline cartilage has low potential for regeneration, numerous methods and techniques have been proposed to induce the reparation process. Microfracture is a convenient procedure for this purpose. However, the quality of the new cartilage after microfracture is still not as proper as original. In this experimental study, we used microfracture in combination with intraarticular application of hyaluronan in rabbit knee articular defect. Bilateral knee arthrotomies, chondral defects, and microfracture were created on each intercondylar notch in thirty rabbits. Rabbits received intraarticular injections of hyaluronan once a week for 3 weeks in the right knee, started from 1 week after injury. The left knees, which served as controls, were injected with normal saline. Biopsy was taken from both knees at the 4th and 6th weeks. In comparison with the control group, after 6 weeks we observed a higher potential for healing in the experimental group, with thicker and more organized repair tissue filling the defect. The current study reveals that application of hyaluronan after the microfracture might be beneficial in inducing articular cartilage defect reparation.     

Ultrastructural study of the olfactory placode in the chick embryo

An ultrastructural study of the nasal placode of chick embryos between the stages 16 to 24 of Hamburger-Hamilton was made. The study describes the disposition of the constituent elements as well as their characteristics.     

The effect of skin expansion on acellular dermis in an experimental model

Objective: Although acellular dermis is widely used in prosthesis-based breast reconstruction, there is no study evaluating its expandability and histological, ultra-structural related changes. The purpose of this study is to determine whether acellular dermis could be expanded and whether the histological changes occurring in the skin with tissue expansion is different from normal when acellular dermis is used.

Methods: Twenty-two male Wistar rats were used in this study. In group 1 (n?=?6), a rectangular-shaped tissue expander with final volume of 35?ml was placed subcutaneously. In group 2 (n?=?6) tissue expander was placed submuscularly. In group 3 (n?=?6), a 4?×?5?cm, acellular dermis was inserted and sutured in place, tissue expander was placed underneath acellular dermis. Group 4 (n?=?4) was control, no procedure was done after creation of a pocket. After day 30, tissue expanders were inflated with 2?ml every 2 days with saline solution. On day 66, midvertical, midhorizontal surface expansion measurements were recorded. Samples were examined macroscopically. Biopsies were taken from mid-point of the expanded full-thickness flap. Histological evaluation, total skin thickness, epidermal thickness, and the amount of vascularisation were measured.

Results: There was no expansion noted on the acellular dermis; however, acellular dermis increased vascularity and decreased the thinning of the overlying skin and thickening of the epidermis when compared to other groups.

Conclusion: Acellular dermis use can be beneficial in implant-based breast reconstruction in terms of morbidity and its tissue support.