B cell emigration directly from the cortex of lymphoid follicles in the bursa of Fabricius

In the peripheral blood (PBL) of juvenile chickens three populations of B cells have previously been distinguished based on life-span and origin of cells within each population. In this report we show that the largest PBL B cell subset, population 1 B cells, which are short-lived cells corresponding to about 60% of PBL B cells and the vast majority of bursal emigrants, exit from the bursa directly from the follicular cortex. This conclusion is based on the specific labeling of rapidly dividing cortical lymphocytes with bromodeoxyuridine, followed by their detection in the periphery prior to the appearance of bromodeoxyuridine labeled cells in the bursa medulla. Furthermore, the rate of emigration of cortical lymphocytes, 1.00 ± 0.1% of PBL B cells per hour, is indistinguishable from the emigration rate of B cells from the bursa as a whole. The anatomical organization of the bursa has evolved to focus gut-derived antigens from the bursal lumen into the lymphoid follicles. The emigration of cortical bursal cells is discussed in relation to the exposure of bursal lymphocytes to extrinsic antigen.     

Osteochondroma and secondary synovial osteochondromatosis

Secondary synovial osteochondromatosis (SOC) is a rare disorder caused by a variety of joint disorders. Two unusual cases of secondary SOC are presented. The first patient is a 43-year-old man with extensive SOC developing within a bursa surrounding an osteochondroma of the pubic bone. The second patient is a 23-year-old man who developed florid and progressive SOC of his hip joint following excision of a femoral neck osteochondroma. SOC recurred despite three excisions over a 15-month period. Imaging was useful in pre-operative diagnosis of bursal SOC in the first patient and in detecting multiple recurrences in the second patient. Both cases illustrate prominent SOC developing secondary to osteochondroma. The different hypotheses regarding bursal and secondary SOC are reviewed. Received: 8 October 1998 Revision requested: 28 October 1998 Revision received: 13 November 1998 Accepted: 16 November 1998     

Chick gonadogenesis following early surgical bursectomy

Left ovaries of bursectomized chick embryos were examined on the 17th day of incubation in comparison to normal and sham-operated controls, by histological and histochemical observations. The results show that in bursectomized embryos the cortex appears irregulary developed, with a significant decrease in the mean thickness and in the percentage of the secondary sex cords in the total cortical area. Furthermore, the germinal epithelium appears thicker and the subcortical medulla and the tunica albuginea more compact. The greater activity of the enzyme ⁵–3-hydroxysteroid dehydrogenase ( ⁵3HSD) found in ovaries of bursectomized embryos (histochemical method) could be related to an endocrine dismetabolism affecting the cortical development. On the basis of these results and those of other authors, some hypotheses are advanced. In particular, an action of the bursal factor on GTH receptors could be the factor responsible of the enhanced steroidogenic activity altering the hormonal environment.     

Effects of Androgen Disruption by DDE on the Development and Functioning of the Immune System in Japanese Quail

We hypothesized that immunosuppression in birds that is caused by exposure to antiandrogenic chemicals occurs mainly through disruption of the development of the androgen-sensitive avian lymphoid organ, the bursa of Fabricius. Injections of 20.0 or 40.0 μg of p,p′-DDE [ethylene, 1,1-dichloro-2,2-bis(p-chlorophenyl)], an antiandrogen, were administered at embryonic day 1. Bursas from only chicks treated with DDE were larger than, had fewer follicles, and exhibited vacuolization within follicles compared with controls; spleens were unaffected. No differences in either immune response test were observed. This study demonstrates that the bursa may play a role in androgen-active endocrine disrupting chemical-induced immunosuppression.     

Drainage tube endoscopy: a contribution to the management of severe acute pancreatitis?

Peritoneal lavage is one of the interventional approaches that have gained some attention in the early, toxaemic phase of acute pancreatitis. Additionally some kind of drainage is necessary for suppurative collections that characterize the late phase of the disease. In both the above situations tube plugging is a common problem and it is usually associated with a relapse of the patient's septic state and newly formed collection(s) on abdominal CT. Two cases are presented, in early and in late phases respectively, in which drainage tube adoscopy (DTE) re-established tube patency and ensured drainage. DTE may represent an alternative to surgery or to CT-guided paracentesis and evacuation of newly formed intra-abdominal collections secondary to tube obstruction. Received: 24 March 1997 Accepted: 7 August 1997     

Synovial cysts of the hip joint and iliopsoas bursitis: A spectrum of imaging abnormalities

Synovium-related soft tissue disease around the hip constitutes a spectrum ranging from isolated iliopsoas bursitis to pure articular synovial herniations without bursal involvement. The clinical, pathologic, and radiographic features of these entities are discussed as they pertain to the variety of underlying disorders which predispose to their occurrence. Nine case reports are utilized to illustrate the variable clinical and radiographic presentations which may be encountered. Based upon these cases as well as those in the literature, an imaging algorithm has been developed which should eliminate unnecessary studies and allow prompt and accurate diagnosis.     

Non-Infectious Ischiogluteal Bursitis: MRI Findings

Objective

We wished to report on the MRI findings of non-infectious ischiogluteal bursitis.

Materials and Methods

The MRI findings of 17 confirmed cases of non-infectious ischiogluteal bursitis were analyzed: four out of the 17 cases were confirmed with surgery, and the remaining 13 cases were confirmed with MRI plus the clinical data.

Results

The enlarged bursae were located deep to the gluteus muscles and postero-inferior to the ischial tuberosity. The superior ends of the bursal sacs abutted to the infero-medial aspect of the ischial tuberosity. The signal intensity within the enlarged bursa on T1-weighted image (WI) was hypo-intense in three cases (3/17, 17.6%), iso-intense in 10 cases (10/17, 58.9%), and hyper-intense in four cases (4/17, 23.5%) in comparison to that of surrounding muscles. The bursal sac appeared homogeneous in 13 patients (13/17, 76.5%) and heterogeneous in the remaining four patients (4/17, 23.5%) on T1-WI. On T2-WI, the bursa was hyper-intense in all cases (17/17, 100%); it was heterogeneous in 10 cases and homogeneous in seven cases. The heterogeneity was variable depending on the degree of the blood-fluid levels and the septae within the bursae. With contrast enhancement, the inner wall of the bursae was smooth (5/17 cases), and irregular (12/17 cases) because of the synovial proliferation and septation.

Conclusion

Ischiogluteal bursitis can be diagnosed with MRI by its characteristic location and cystic appearance.     

The MRI appearance of cystic lesions around the knee

This review presents a comprehensive illustrated overview of the wide variety of cystic lesions around the knee. The aetiology, clinical presentation, MRI appearances and differential diagnosis are discussed. Bursae include those related to the patella as well as pes anserine, tibial collateral ligament, semimembranosus–tibial collateral ligament, iliotibial and fibular collateral ligament–biceps femoris. The anatomical extension, imaging features and clinical significance of meniscal cysts are illustrated. Review of ganglia includes intra-articular, extra-articular, intraosseous and periosteal ganglia, highlighting imaging findings and differential diagnoses. The relationship between proximal tibiofibular joint cysts and intraneural peroneal nerve ganglia is discussed. Intraosseous cystic lesions, including insertional and degenerative cysts, as well as lesions mimicking cysts of the knee are described and illustrated. Knowledge of the location, characteristic appearance and distinguishing features of cystic masses around the knee as well as potential imaging pitfalls such as normal anatomical recesses and atypical cyst contents on MR imaging aids in allowing a specific diagnosis to be made. This will prevent unnecessary additional investigations and determine whether intra-articular surgery or conservative management is appropriate.     

Transplantation Opportunities of Hepatitis C Virus–Seropositive Patients on the Kidney Waiting List

Objective

Besides severe organ shortage, hepatitis C virus (HCV) infection is an important obstacle for kidney transplantation because of long waiting times on deceased kidney donor waiting lists. We aimed to evaluate calling number of candidates according to HCV serology.