Umbilical Stalk Research Articles

UREKA: Umbilical Ring Easy Kannula Access

Standard techniques of laparoscopic access involve creating an abdominal wall defect and can result in complications. We describe the umbilical ring easy kannula access (UREKA) technique, evaluating safety and a decrease in complications related to port placement. UREKA is performed via a supra- or infraumbilical incision followed by circumferential dissection of the umbilical stalk. The umbilical skin is dissected free from the fascia, exposing the umbilical ring. Pneumoperitoneum is established either before or after placement of a dilating port through the open ring. We reviewed all laparoscopic procedures performed by one pediatric surgeon over 14 months using UREKA. Ninety-four patients underwent laparoscopic surgery with initial port placement via UREKA. Appendectomy (n=57) was the most common procedure, followed by fundoplication (15) and cholecystectomy (10). No intestinal, solid organ, vascular, or bladder injuries related to port placement occurred. The only postoperative complication was a superficial wound infection in a 135-kg patient following cholecystectomy, treated successfully with oral antibiotics alone. The umbilical ring persists to some degree in all pediatric patients and provides a safe portal of entry for laparoscopic surgery. UREKA has few complications and is a straightforward, reproducible technique for gaining initial laparoscopic access.

A Safe Quick Technique for Placement of the First Access Port for Creation of Pneumoperitoneum

Closed and open techniques for creation of pneumoperitoneum are being used simultaneously with varying frequencies. Some studies analyzing slight modifications to both approaches have been published and others are under way. We conducted this study to eliminate some of the disadvantages of the open technique, an already proven safer technique. In a total of 1250 consecutive patients, who underwent various laparoscopic procedures, a modified open technique was used. This technique involves identification and incision of a point at a junction of the umbilical stalk and linea alba infraumbilically. With this technique, penetration of a blunt trocar was possible under direct vision with minimal and controlled axial force. Time needed to induce pneumoperitoneum, intraoperative (vascular and other organ injury) and postoperative complications were recorded, and data were analyzed. Intraabdominal access was successfully achieved in all cases without any vascular or solid organ injury except in 3 (0.24%) cases. In these 3 cases, the procedure failed due to severe adhesions, because of previous abdominal surgeries. Mean time taken to induce pneumoperitoneum was 4.0 minutes (range, 2 to 9.5), while time required to close the first access port was 4.5 minutes (range, 3 to 8). Enterotomy occurred in 2 (0.16%) cases, while a postoperative port-site hernia occurred in 2 (0.16%) cases. Port-site infection occurred in 6 (0.48%) cases, and port-site hematoma in 4 (0.32%) cases. Gas spillage was recorded in only 6 (0.48%) cases. We recommend a modified open technique as the technique of choice in all cases requiring laparoscopic surgery in general and developing countries in particular where intraabdominal adhesions are not uncommon.

Open versus close pneumoperitoneum: A pursuit for safer technique

Objective: Pneumoperitoneum is a prerequisite in all laparoscopic procedures. This is a very vital step and is still a matter of concern and a subject of further evaluation. Two basic methods commonly used with some modification are closed (veress needle) and open (Hasson) techniques and none of technique has proved to be better than other. We carried out this study to compare the two techniques in terms of access related complications and time consumed during creation of pneumoperitoneum and closure of port wounds. Methodology: A comparative randomized prospective study was conducted in department of surgery. 475 patients were finally evaluated, 223 were randomized for open (Hasson) while 232 for closed (veress) technique. In open technique slight modification was used by making incision at junction of umbilical stalk and linea alba, while standard veress needle technique was used in closed group. Operative and post operative complications were recorded and analyzed. Results: Mean time required to create pnemoperitoneum was significantly less with open group (6.61±3.89 minutes) compared to closed group (8.18±3.39 minutes). Time required to close port wounds was also significantly less with open group as compared to closed group (7.41±1.87 versus 10±2.44 minutes). No mortality and major complication regarding vascular and solid organ injury was recorded in both groups. Failure of procedure was observed in 4 cases (1.72%) in closed group and one case (0.44%) in open group. Bowel injury was recorded in two cases in closed group however it was not significant statistically. Other minor injuries were not significant on comparing both groups. Conclusion: Open technique is safe and quicker. We recommend this method in all cases of laparoscopy requiring access into abdominal cavity.

Efficacy of a new navel dip to prevent umbilical infection in dairy calves.

A field study was conducted utilizing 495 newborn calves in 13 commercial Wisconsin dairy herds to evaluate the use of a new umbilical disinfectant dip (Navel Guard (NG), Sirius Chemical Group, McDonough, GA) to prevent umbilical infections (omphalitis) as compared to control groups (CG): (1) not dipping the umbilicus at birth (CGNodip; trial conducted in two herds), (2) dipping the umbilicus with 7% tincture of iodine (CG7TI; trial conducted in seven herds), or (3) dipping with solutions containing a low concentration (0.5 to 2%) of iodine (CGILow; trial conducted in four herds). In all three trials, newborn calves were alternately assigned (every other calf) to have their navel dipped with either NG or the control article (CGNodip, CG7TI or CGILow) as soon as possible after birth. A study technician evaluated each calf's navel once per week for the first three weeks of life by measuring the diameter of the umbilical stalk and determining whether a painful response was elicited upon palpation of the umbilicus. Results indicate that Navel Guard was more effective for reducing the incidence of umbilical infections in neonatal calves compared to calves not dipped shortly after birth. The risk for umbilical infection was numerically, but not statistically, reduced in calves when the umbilicus was dipped with Navel Guard as compared to calves for which the umbilicus was dipped with 7% tincture of iodine or solutions containing low concentrations of iodine (0.5 to 2.0%).

Long-Term Results of a Versatile Technique for Umbilicoplasty in Abdominoplasty

Umbilical repositioning is a main step in performing abdominoplasty. The surgical aims are minimal visible scars and a natural-appearing result. Reported techniques do not completely satisfy the aesthetic targets for all types of patients. A previous study reported a versatile technique for umbilicoplasty based on an elliptical vertical incision of the umbilical skin and a double opposing "Y" incision on the abdominal flap to create a new umbilicus. This report describes the long-term results with this technique. A total of 111 abdominoplasties were performed. Patient satisfaction and postoperative results were evaluated over a 5-year follow-up period. A modified 5-ml syringe was used to assess the depth and volume of the umbilical stalk. Depth value variations were statistically compared using the Wilcoxon test. For all the patients, a three-dimensional umbilicus with an adequate depression was created. In four cases, deepithelialization of the umbilical skin occurred. After 1 postoperative year, no significant changes in umbilical shape, dimension, depth, or appearance were observed. After 5years, no significant changes in shape or appearance were observed. The cicatricial umbilical stenosis occurrence was 4.5%. A small significant decrease in umbilical depth was noted. Overall, the results remained satisfying at this writing. The reported technique is easy to learn, simple to perform, and stable over time. It gives a natural depth appearance, ensures optimal position, pulls scars deeply, and allows achievement of different shapes according to the patient's habitus.

Pathogenic implications of remnant vitelline structures in gastroschisis

PurposeThe pathogenesis of gastroschisis is unknown. It may be helpful in understanding its pathogenesis to know the structural relationships among umbilical components including umbilical vessels, urachus, and vitelline structures, and thus, the authors investigated the remnants of vitelline structures in a series of cases of gastroschisis. MethodsMedical records of 41 cases with gastroschisis treated in our institute from 1979 to 2009 were retrospectively reviewed. ResultsParaumbilical bands, possible remnants of vitelline structures, were observed in 4 cases (9.8%). All 4 bands were attached to the skin edge of the abdominal defect without incorporation into the umbilical cord. The band ended at the mesentery in 3 cases and at the antimesenteric site of the ileum in the remaining case. Histologic findings showed fibrous tissues in all cases. One was possibly associated with the development of colonic atresia. Another was noticed after silo reduction when herniated bowels became strangulated by the band. The other 2 cases were uncomplicated. ConclusionsOur findings may support the recently proposed hypothesis that the developmental failure of the yolk sac and related vitelline structures to merge with or to be incorporated into the umbilical stalk might be associated with the pathogenesis of the abdominal wall defect in gastroschisis. Paraumbilical bands derived from vitelline structures may possibly cause intestinal ischemia prenatally or postnatally.

Neoumbilicus in abdominoplasty: points of finesse

Most of the scar and resulting ‘dog ears’, as a result of abdominoplasty, are inconspicuous and can be well hidden in the clothing. Neoumbilicus is often at display and an aesthetically pleasing umbilicus heightens the patient satisfaction from such a procedure. This paper discusses our technique of restoration of the umbilicus. The neoumbilical site is marked 1 cm inferior to the projected stalk. A small ellipse is excised and a core of adipose tissue is excised in a conical fashion underneath it. The umbilicus is anchored to the rectus sheath at 3, 9 and 6 o’clock points in the described manner. We then discuss the importance of the vector of pull on the umbilical stalk and relate this to production of an aesthetically pleasing superior hood. The technique creates an aesthetically pleasing umbilicus that is sited in a gentle depression, with a superior hood. The technique has been used on 40 patients in the last 4 years who have been followed up for at least 6 month. The various points of finesse and the details of the senior author’s technique are presented by means of illustrations and photographs.

Basal Cell Carcinoma Invading the Umbilical Stalk Excised with Mohs Micrographic Surgery: Case Report and Review of Umbilical Anatomy

Basal Cell Carcinoma Invading the Umbilical Stalk Excised with Mohs Micrographic Surgery: Case Report and Review of Umbilical Anatomy

Escape of the yolk sac: a hypothesis to explain the embryogenesis of gastroschisis

Gastroschisis is a significant birth defect that in many countries has shown an increased prevalence in recent decades, and the change has affected primarily younger mothers. Despite numerous epidemiological studies no other consistent associated risk factor has been identified. In this paper we review the five main theories related to the pathogenesis of this malformation and outline the reasons why we think none fully explains the embryogenesis of gastroschisis. We briefly present some clinical observations we have made that we consider germane to the pathogenesis and outline a hypothesis that we think can account for the origins of this malformation. Our proposal is that the determining defect in gastroschisis is failure of the yolk sac and related vitelline structures to be incorporated into the umbilical stalk. Otherwise, ventral closure of the lateral abdominal walls occurs normally, thus orphaning the vitelline duct and yolk sac outside both the main body stalk and the abdominal wall. Thus, in addition to the umbilicus, the abdominal wall has a separate perforation through which the midpoint of the gut is attached to the exteriorized vitelline structures. This connection through the ventral wall prevents normal egress of the gut into the umbilical cord during the second month of development and acts as the egress point for the gut resulting in gastroschisis.

Pyloromyotomy through an Infraumbilical Incision: Open Technique and Superb Cosmesis

The optimal incision for pyloromyotomy remains controversial. A new pyloromyotomy incision has been developed. The incision is placed circumferentially in the infra-umbilical crease, and accesses the pylorus after dividing the umbilical stalk and enlarging the natural umbilical defect. After the pyloromyotomy, the fascia is closed, simultaneously repairing any concomitant umbilical hernia. Patients were followed up at 2 weeks and at three months after operation. The results of the first 14 consecutive operations over a 5-month period by, or under the supervision of, one staff surgeon are reported. All 14 pyloromyotomy were successfully completed through the infra-umbilical incision. The series included 4 patients with metabolic alkalosis requiring preoperative correction. One duodenal perforation was recognized and repaired. Mean age and weight of the patients was 31.2 days (range 13-55), and 3 754 g (range 2,880-5,400), respectively. Mean operation time was 28.4 minutes (range 17-46). Mean duration between operation and discharge was 1.93 days (range 1-6), and mean total hospital stay was 2.8 days (range 1-8). There were no immediate or delayed wound complications. A virtually scarless appearance was seen in all patients on follow-up. A new infra-umbilical pyloromyotomy combines the benefits of the laparoscopic and open approaches and results in superb cosmesis.

A Versatile Technique for Repositioning of the Umbilicus in Abdominoplasty

Sir: Umbilical repositioning is a main step during abdominoplasty. The surgeon aims for minimal visible scars and a natural-looking result.1 Several techniques have been described, but none of them completely satisfy the aesthetic targets in all patients. Evidence of scar or retraction with umbilical stenosis may occur.2 The use of Y or double-Y cutaneous incisions has improved aesthetic results.3,4 We introduce a versatile technique for umbilicoplasty: an elliptical vertical incision of the umbilical skin and a double-opposing Y incision on the abdominal flap, to create a stable, natural-looking umbilicus. A prospective, open-label study was performed. Forty patients underwent abdominoplasty using the present technique for umbilicus repositioning. Patient age ranged between 24 and 63 years (36 women and four men). Body mass index ranged from 26 to 47 kg/m2 (mean, 33 kg/m2). Patient satisfaction and postoperative results were evaluated over a 12-month follow-up period. A modified 5-ml syringe was used to assess the depth and volume of the umbilical stalk. Variations in depth between 1 and 12 months were statistically compared using the Wilcoxon test. The umbilical skin is sharply incised vertically. The umbilical pedicle blood supply is preserved. The umbilical dermis is attached to the abdominal rectus fascia in four cardinal points with polyglecaprone 25 4–0 suture. In patients with a thin habitus, it is important to plicate the periumbilical fascia sufficiently to create an inverted umbilicus. The elliptical umbilical island is tightened against the tensed abdominal fascia without distortion. The site of umbilicus repositioning is determined by its projection on the abdominal flap. A small, double-opposing Y cutaneous incision is made in this point. The vertical size must be approximately the same as that of the original umbilicus. The angle and size of the four lateral incisions can be modified according to the width we want to obtain. Defatting is performed through the double-opposing Y incision. The umbilical skin is sutured to the surrounding abdominal skin with 4–0 nylon sutures. Four of these sutures are left longer and tied over a paraffin gauze patch to ensure deep umbilicus positioning. In all patients, an umbilicus with adequate depression was created. In one case, de-epithelization of the umbilical skin occurred and healed spontaneously in 2 weeks. After 12 months, no significant changes in shape, dimension, and appearance were observed. All patients were pleased with the final result. No cicatricial umbilical stenosis occurred, and no statistical significance was found comparing mean depth variations between 1 and 12 months (10.67 ± 1.34 ml and 10.4 ± 1.19, respectively; p = 0.0543). This technique gives a natural depth appearance, ensures optimal position, pulls scars deeply, avoids visible scarring, and allows achievement of different shapes according to the patient’s habitus (Figs. 1 and 2). Any umbilical size, in either obese or thin patients, can be created with this method. The double-opposing Y incision reinforces the vertical shape, creates natural umbilical dimpling, and prevents stenosis with stable results. This technique is easy to learn and simple to perform, effectively hides scars, and gives a youthful appearance to the umbilicus.Fig. 1.: Preoperative view of the umbilicus.Fig. 2.: Twelve-month postoperative view.Marco Mazzocchi, M.D., Ph.D. Luca A. Dessy, M.D. Andrea Figus, M.D. Department of Plastic Surgery University “La Sapienza” Rome, Italy DISCLOSURE The authors did not receive any financial support for this study, nor were they in any way commercially involved with any company.

CLOSTRIDIUM PERFRINGENS BACTEREMIA IN A PATIENT WITH SMALL BOWEL LYMPHOMA AND MECKELʼS DIVERTICULUM

A 87 year old male with HTN, CVA, BPH, DJD, & appendectomy was admitted to the hospital with one day history of diarrhea, bilious vomiting & transient periumbilical discomfort. He denied fever, chills, NSAID use, unusual food intake or recent travel. He was on celecoxib, aspirin, & Hyzaar. The physical exam was unremarkable except for mild right lower quadrant abdominal discomfort without guarding or rebound. The lab evaluation showed mild leukocytosis, iron deficiency anemia, normal LDH & ESR. The blood culture was positive for C perfringens. The x-ray abdomen showed mildly distended small bowel loops. The CT scan of the abdomen showed small bowel wall thickening. The EGD & colonoscopy were negative. A CT scan 1 month later showed segmental thickening of the small bowel with enlarged mesenteric lymph nodes & omental infiltration suspicious for a neoplastic process. Laparotomy showed a mid ileal mass and a Meckel's diverticulum adherent to the umbilical stalk. A partial small bowel resection with primary anastomosis & Meckel's diverticulectomy were performed. The histopathology showed diffuse large B-cell lymphoma. A bone marrow biopsy was negative for lymphoma. The patient was referred to an Oncologist. Discussion: Small bowel lymphomas occur in about 9% of patients with GI tract non-Hodgkin's lymphomas (NHL). They account for up to 75% of primary GI tract lymphomas in Middle East & Mediterranean countries. The median age of patients with non immunoproliferative small intestinal disease (non-IPSID) lymphomas is 37 yrs with male preponderance. Common presenting symptoms are abdominal pain (75%), anorexia (41%), & weight loss (34%). GI bleeding is uncommon. The non-IPSID lymphomas are usually unifocal, appearing as ulcerated, protruding, or infiltrating mass in the distal small intestine. The B-cell intestinal lymphomas are uncommon and usually low-grade. The primary treatment is usually surgical resection followed by whole-abdominal irradiation and/or chemotherapy. The 1-year survival is up to 75%. There are few reported cases of lymphoma associated with Meckel's diverticulum especially within the Meckel's diverticulum. C perfringens bacteremia has not been reported as an initial presenting symptom of intestinal lymphoma. There are only two case reports of C perfringens bacteremia in patients with NHL undergoing chemotherapy. Both reported cases had colonic perforation.

The arterial vascularisation of the abdominal wall with special regard to the umbilicus

Aim. In order to prevent wound healing problems around the transposed umbilicus following abdominoplasty, we investigated the arterial vascularisation of the abdominal wall with special regard to the umbilicus. The aim was to optimise the planning of the umbilical stalk and flap design.Method. The inferior and superior epigastric arteries of 12 cadavers (mean age 83 years) were injected with barium-sulphate, lead-mennige and gelatine. The abdominal walls were resected en bloc and X-ray photographs were taken by conventional and mammographic technique.Results. The radiographic examination showed that the main trunks of the epigastric vessels follow an ‘hour-glass’ or ‘rhomboid’ pattern around the centromedial umbilicus. Each main trunk splits into two obligate branches one medial and one lateral. The anastomosis between the inferior and superior epigastric artery is located above the umbilicus. The umbilicus is nourished by separate axial vessels originating from the inferior epigastric artery. It was also shown that the inferior intercostal arteries anastomose with the branches of the inferior and superior epigastric artery.Conclusion. Dividing the abdominal wall into four quadrants around the central umbilicus, the lateral areas of the lower quadrants show the weakest vascularisation by the inferior epigastric artery. This fact may cause healing problems after surgery in this area. The axial vascularisation of the umbilicus makes any torsion or traction a potential hazard to the umbilical flap during abdominoplasty especially by re-siting the umbilicus. The anatomical study showed clearly the benefit of preparing a broad base fat layer with a generous diameter of incision line around the umbilicus.

Natural-looking umbilicus as an important part of abdominoplasty.

The umbilicus is an important and essential aesthetic component of the abdomen. Many surgeons use different methods to relocate umbilicus during abdominoplasties. We prefer to use a simple combination of different well-known principles to form the neo-umbilicus. The main steps of the procedure are to make an elliptical vertical incision, to do vertical abdominal fascial plication, to embed the umbilical stalk in this plication by suturing the umbilical skin and the rectus fascia together to maintain the umbilical dimple, to place it at the vertical incision made in the abdominal skin at a predetermined point. Silk sutures are used for the abdominal fascial plication and neo-umbilical fixation. Liposuction from the neo-umbilicus to xiphoid along the midline of the upper abdomen creates a minimal superior sulcus. In each patient, a three-dimensional umbilicus with sufficient depression was obtained. All patients, including one case with complications, were pleased by the final aesthetic results.

Umbilical stalk technique for establishing pneumoperitoneum.

The Veress needle technique for establishing pneumoperitoneum is widely used yet associated with slow insufflation and potentially life-threatening complications. The open or Hasson technique is relatively safer but considered cumbersome by many. We describe a mini-open technique that uses a 5-mm transumbilical incision and placement of a 5-mm blunt cannula without the trocar. We have employed this technique for 4 years in 600 patients without a midline laparotomy incision incorporating the umbilicus and have accessed the abdomen safely for laparoscopy without any complications. The time from skin incision to the start of the procedure is usually under 2 minutes. Our umbilical stalk technique provides rapid and safe access to the abdomen, eliminating the dangers of a blind sharp needle or trocar insertion and the need for a larger incision with placement of stay sutures. We recommend this simple technique for entry into the uncomplicated abdomen.

Simplified technique for creating a youthful umbilicus in abdominoplasty.

Reimplantation of the umbilicus remains a critical aesthetic component in abdominoplasty and transverse rectus abdominis musculocutaneous breast reconstruction. Although the ideal shape of the umbilicus has been debated, recent studies have shown the young, thin female with an attractive abdomen tends to have a small, vertically oriented umbilicus. The aesthetic considerations for reimplantation include position, depth, shape, and location of scar. The authors present a technique that is expedient and reliable and that addresses each of these variables. The umbilicus is sutured to the rectus fascia and reimplanted through a vertical incision in the abdominal flap. Subdermal sutures are placed from the umbilicus to the linea alba superiorly and inferiorly. These sutures create a vertically oriented shape and place the umbilicus in the midline. Shortening the umbilical stalk establishes depth and hides the closure of the umbilicus and abdominal flap within the stalk. The stalk length is easily varied, depending on the thickness of the panniculus. Defatting is performed through the vertical incision to allow easy visualization of the umbilicus. This technique creates depth, ensures optimal position, pulls the scar deep in the umbilicus, and produces a vertically oriented, youthful umbilicus. More importantly, a questionnaire given to patients who have undergone abdominoplasty with this procedure (n = 21) confirms that patients have a high level of satisfaction with the resulting shape, position, and overall appearance.

Refinements in transverse rectus abdominis myocutaneous flap breast reconstruction: projection and contour improvements.

A surgical procedure with the transverse rectus abdominis myocutaneous (TRAM) flap for breast reconstruction is presented using parameters from the opposite normal breast to achieve a better cone shape in the new breast to project the nipple-areola complex. This cone projection is obtained through a vertical plication of both skin/fat halves of the TRAM flap and with two supraumbilical fat flaps to avoid cone collapse. The infraclavicular and axillary regions are filled with a de-epithelialized "fish-fin" cutaneous-fat or fat-only flap, which is placed as a lateral TRAM extension. The de-epithelialized lateral extremity of the TRAM flap folded over itself gives a mound shape to the lateral aspect of the new breast, and the inverted umbilical stalk attached to the TRAM flap imitates a nipple. This procedure is based on six breast reconstructions with a 2-year follow-up. The procedure is a simple, safe, and versatile way to mimic the opposite breast. It is mostly indicated for thin patients who have small to moderate breasts without ptosis or hypertrophy who refuse breast implants or request a mastopexy or reduction mammaplasty on the opposite normal breast during the same procedure.

Umbilicoplasty in Abdominoplasty: A Demonstration

Introduction: The purpose of this paper is to demonstrate a new technique in performing umbilicoplasty at the time of abdominoplasty that avoids the formation of a thickened or contracted circular scar. Materials and Methods: After a routine abdominoplasty and isolation of the umbilical stalk with extra redundant skin surrounding the umbilicus, a V-incision is made in the abdominal wall skin at a site selected for the new umbilical site. The superior or cephalic part of the umbilicus is split and spread, creating the appearance of a wedge that has been removed. The umbilicus is brought through the abdominal wall opening. The inferior point created by the abdominal V is sutured to the slit point of the umbilicus, which is cephalic, and is also sutured to the fascia at the base of the stalk, thus rotating the point of the V deep into the umbilicus and avoiding a circular scar. Results: The resultant umbilicus has no scar superiorly, as the tip of the V is completely buried. Thus, a visible circular scar is avoided. Discussion: The described procedure is simple, and the results are cosmetically acceptable both to the patient and the surgeon.

VEGF and VEGF-C: Specific Induction of Angiogenesis and Lymphangiogenesis in the Differentiated Avian Chorioallantoic Membrane

The lymphangiogenic potency of endothelial growth factors has not been studied to date. This is partially due to the lack ofin vivolymphangiogenesis assays. We have studied the lymphatics of differentiated avian chorioallantoic membrane (CAM) using microinjection of Mercox resin, semi- and ultrathin sectioning, immunohistochemical detection of fibronectin and α-smooth muscle actin, andin situhybridization with VEGFR-2 and VEGFR-3 probes. CAM is drained by lymphatic vessels which are arranged in a regular pattern. Arterioles and arteries are accompanied by a pair of interconnected lymphatics and form a plexus around bigger arteries. Veins are also associated with lymphatics, particularly larger veins, which are surrounded by a lymphatic plexus. The lymphatics are characterized by an extremely thin endothelial lining, pores, and the absence of a basal lamina. Patches of the extracellular matrix can be stained with an antibody against fibronectin. Lymphatic endothelial cells of differentiated CAM show ultrastructural features of this cell type. CAM lymphatics do not possess mediae. In contrast, the lymphatic trunks of the umbilical stalk are invested by a single but discontinuous layer of smooth muscle cells. CAM lymphatics express VEGFR-2 and VEGFR-3. Both the regular pattern and the typical structure of these lymphatics suggest that CAM is a suitable site to study thein vivoeffects of potential lymphangiogenic factors. We have studied the effects of VEGF homo- and heterodimers, VEGF/PlGF heterodimers, and PlGF and VEGF-C homodimers on Day 13 CAM. All the growth factors containing at least one VEGF chain are angiogenic but do not induce lymphangiogenesis. PlGF-1 and PlGF-2 are neither angiogenic nor lymphangiogenic. VEGF-C is the first lymphangiogenic factor and seems to be highly chemoattractive for lymphatic endothelial cells. It induces proliferation of lymphatic endothelial cells and development of new lymphatic sinuses which are directed immediately beneath the chorionic epithelium. Our studies show that VEGF and VEGF-C are specific angiogenic and lymphangiogenic growth factors, respectively.

A RETROSPECTIVE STUDY OF UMBILICAL SONOGRAPHY IN CALVES

The purpose of this study was to assess the usefulness of diagnostic ultrasound for the detection of umbilical defects in calves. The medical records of 25 calves having undergone an ultrasound examination and for which a final diagnosis was available were reviewed retrospectively. Ultrasound was accurate (p = 0.05) for the diagnosis of umbilical defects in calves. Overall sensitivity (0.89) and specificity (0.83) were similar. Ultrasound was a better predictor of abnormal (PV' = 0.94) than normal PV‐ = 0.71) structures. Ultrasound was a good predictor (p < 0.05) of disease and normalcy in all umbilical region subdivisions except the umbilical vein (p = 0.16). Specificity was greater than sensitivity in all areas except the umbilical stalk. Sensitivity was lowest (0.50) for detection of umbilical herniae and lesions in the umbilical vein. When multiple umbilical areas were affected, ultrasound identified all lesions in 4 of 7 calves. Criteria determined to be subjectively useful in the sonographic diagnosis of infection in umbilical remnants were gas andlor echogenic fluid in the lumen and a thickened, hypoechoic wall.