This study examined the morphologic features of the parietal peritoneal membranes of 130 patients undergoing peritoneal dialysis (PD) and compared them with the features of the peritoneal membranes of normal individuals, uremic predialysis patients, and patients undergoing hemodialysis. The median thickness of the submesothelial compact collagenous zone was 50 µm for normal subjects, 140 µm for uremic patients, 150 µm for patients undergoing hemodialysis, and 270 µm for patients undergoing PD (P 97 mo, 700 µm (n = 19)]. Vascular changes included progressive subendothelial hyalinization, with luminal narrowing or obliteration. These changes were absent in samples from normal subjects but were present in 28% of samples from uremic patients and 56% of biopsies from patients undergoing PD. In the PD group, the prevalence of vasculopathy increased significantly with therapy duration (P = 0.0001). The density of blood vessels per unit length of peritoneum was significantly higher for patients with membrane failure and was correlated with the degree of fibrosis (P = 0.01). For the first time, a comprehensive cross-sectional analysis of the morphologic changes in the peritoneal membranes of patients undergoing PD is provided. The infrequency of fibrosis in the absence of vasculopathy suggests that vasculopathy may predispose patients to the development of fibrosis. This study provides a sufficiently large cohort of samples to allow structure-function relationships to be established, as well as providing a repository of tissue for further studies.

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Morphologic Changes in the Peritoneal Membrane of Patients with Renal Disease

Lymphedema-edema that results from chronic lymphatic insufficiency-is a chronic debilitating disease that is frequently misdiagnosed, treated too late, or not treated at all. There are, however, effective therapies for lymphedema that can be implemented, particularly after the disorder is properly diagnosed and characterized with lymphoscintigraphy. On the basis of the lymphoscintigraphic image pattern, it is often possible to determine whether the limb swelling is due to lymphedema and, if so, whether compression garments, massage, or surgery is indicated. Effective use of lymphoscintigraphy to plan therapy requires an understanding of the pathophysiology of lymphedema and the influence of technical factors such as selection of the radiopharmaceutical, imaging times after injection, and patient activity after injection on the images. In addition to reviewing the anatomy and physiology of the lymphatic system, we review physiologic principles of lymphatic imaging with lymphoscintigraphy, discuss different qualitative and quantitative lymphoscintigraphic techniques and their clinical applications, and present clinical cases depicting typical lymphoscintigraphic findings.

https://jnm.snmjournals.org/content/jnumed/44/1/43.full.pdf

Who is at risk for developing chronic anal fistula or recurrent anal sepsis after initial perianal abscess

Background. Peritoneal infection and poor ultrafiltration continue to be the major causes of treatment failure in CAPD. The combined effects of peritonitis and the continuous exposure to dialysis fluid remain the most likely candidates affecting the peritoneum in the long term. The purpose of this study was to observe the effects of peritonitis and dialysis on longitudinal peritoneal function. Methods. The peritoneal equilibration test (PET) was utilized to quantify longitudinal changes in lowmolecular-weight solute transfer (D/Pcreat) and ultrafiltration (UF) in 233 patients treated with CAPD. Of these, 166 represented an unselected cohort (Group 1) studied prospectively from commencing treatment for up to 54 months, and 67 were selected patients (Group 2) with PET data available at commencement of the study, having been on dialysis for a minimum of 18 months. PETs were performed either 6-monthly or following peritonitis episodes. Results. Data on the short-term effect of peritonitis kinetics were pooled for groups 1 and 2. Single, isolated episodes (« = 86) had no significant effect on D/Pcreat or UF, whereas recurrences or clusters of infection (n = 70) caused increases in D/Pcreat and reductions in UF, the significance of which increased with the number of episodes. There were significant correlations between both changes in D/Pcrcat and UF with the cumulative dialysate leukocyte count, regardless of infecting organism, suggesting that intensity of peritoneal inflammation is also important. Those organisms associated with greater change in peritoneal kinetics, e.g. S. aureus, Pseudomonas, also had the highest neutrophil counts. The longitudinal changes in peritoneal kinetics were analysed for patients in group 1 only. There was a highly significant increase in D/Pcreat after 6 months treatment; this increased further with time on treatment, reaching further significance at 42 and 48 months. There was an associated reduction in UF. In view of the short-term effects of peritonitis on kinetics Correspondence and offprint requests to: Dr S. J. Davies, Department of Nephrology, Princes Road, Hartshill, Stoke-on-Trent ST4 7LN, UK. group 1 was further subdivided into patients who were either peritonitis free or only experienced isolated infections, group la, and those that had multiple infection episodes, group lb. Treatment drop-out, due to death or technical failure occurred at double the rate in group lb, who also had significantly higher D/Pcreat and lower UF at 1, 6, 12, 18 and 24 months of treatment. Group la subsequently caught up, however, indicating that peritonitis is not the only factor influencing long-term changes in peritoneal kinetics. Conclusions. These data suggest that solute transfer increases and UF declines with time on peritoneal dialysis. This process is exacerbated and accelerated by peritonitis, and appears to be proportional to the degree of associated inflammation and number of infections in close proximity.

Longitudinal changes in peritoneal kinetics: the effects of peritoneal dialysis and peritonitis

The utilization of the peritoneal cavity for dialysis creates the opportunity for alterations in the function and structure of the peritoneal membrane. The peritoneal membrane has proven, however, to be a remarkably resilient organ. Indeed, several studies have documented the functional stability of the membrane in short and midterm evaluations (1–5). One is reminded of the spectacular observations in a small number of patients examined at autopsy who had minimal structural changes despite recurrent infectious complications (6). These isolated observations illustrate the fact that the response of the peritoneal membrane to potentially modifying factors can be diverse, and generalizations on both the immunity to change or the proclivity to widespread change err in their extremism. Further, despite notable attempts at various time points in the history of peritoneal dialysis (PD) to examine the peritoneum of patients on PD (6–12), the scope of changes and the natural history of the peritoneal membrane during dialysis have not been fully elucidated. This is clearly due to the limitation of clinical material to examine and the possibly biased nature of samples that are examined. Further, the techniques of morphologic analysis have been gradually maturing; the targets of examination have also evolved. One structural modification of the peritoneum that has caused significant concern over the fate of dialysis patients is what has been labeled sclerosing encapsulating peritonitis. This entity is not unique to dialysis patients, it occurs in a variety of other clinical conditions discussed below. The multiplicity of suspected etiologies and the confusion over its pathophysiology are reflected in the variety of terms that have been used indiscriminately and interchangeably to describe this complication, such as peritoneal fibrosis, peritoneal sclerosis, sclerotic thickening of the peritoneal membrane, sclerotic obstructive peritonitis, calcific peritonitis, abdominal cocoon, and sclerosing peritonitis (13–34). The most common term used in the nephrology literature in recent years has been sclerosing encapsulating peritonitis, but the popularity of the term does not necessarily validate its continued use, as it is marred by its morphologic inaccuracy, particularly in its reference to an inflammatory component that is frequently absent in the developed syndrome (peritonitis). A more accurate description would be encapsulating peritoneal sclerosis (EPS), which is more descriptive of the morphologic changes.

Encapsulating peritoneal sclerosis : Definition, etiology, diagnosis, and treatment

ObjectiveTo analyze morphological changes in the peritoneum of peritoneal sclerosis (PS) patients. Emphasis was put on vascular abnormalities, because the continuous exposure to glucose-based dialy...

Vascular and interstitial changes in the peritoneum of CAPD patients with peritoneal sclerosis

In the last 3 years we performed 52 peritoneal biopsies (PB) in 31 patients on continuous ambulatory peritoneal dialysis (CAPD). Samples of the parietal peritoneum were obtained either during insertion of the catheter or while it was being repositioned or removed. PB was performed in 13 patients before initiating CAPD and in 27 after 7-49 months of CAPD while 7 had PB during peritonitis, and, again, in 5 of these cases, PB was repeated after 1-4 months for light, electron transmission, and scanning electron microscopy. BP after CAPD showed that mesothelial cells were irregularly spaced, and at times we observed alterations in the cellular structure. Rarely were these cells degenerating, while rarefaction and in many cases complete absence of microvilli were observed. In some cases the submesothelial layers showed rarefaction of the connective tissue and sclerosis. During peritonitis, PB showed more alterations with marked degeneration and in some cases necrosis of the mesothelium and alterations of connective tissue. PB performed some months after peritonitis showed only a partial regression of these alterations and sclerotic patches, and no microvilli were noted in the mesothelium.

Morphology of the peritoneal membrane during continuous ambulatory peritoneal dialysis.

The innervation of lymph vessels in guinea pig mes­entery was studied by light and electron microscope using histochemical techniques. The cholinergic fibers run prevalently longitudinal in the perivascular connective tissue, only brief segments show a loose network. The lymph vessels wall, compared with that of blood vessels, shows few adrenergic nerve  fibers locate d in the adventitia outside the  smooth  muscle cells. The possible role of the nervous system in the Motor control of  the lymph  vessels is discussed .

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Cholinergic and adrenergic innervation of mesenterial lymph vessels in guinea pig

Little has been published on the histochemical and cytochemical properties of anchoring filaments of initial lymph vessels. Previous research suggests that the microfibrils of the anchoring filaments have ultrastructural, histochemical and cytochemical characteristics similar to those of the microfibrils associated with elastic fibers. With the aim of further investigating the histological identity of anchoring filaments, we performed an immunohistochemical study with human skin lymphatics, using antibody HB8, specific for elastic fiber microfibrils. The findings suggested strong molecular similarities between elastic fibers and the fibrils of anchoring filaments of the initial lymph vessels. A comparison of these fibrils showed both constitutional homogeneity and structural continuity from the abluminal surface of the initial lymph vessel to the perivascular elastic fibers and to the adjacent elastic network of connective tissue. In conjunction with previous findings, we propose a unified hypothesis that the elastic fiber system composed of anchoring filaments, perilymphatic sheath and adjacent connective tissue acts by alternating stretching and relaxation to propel lymph towards lymph collectors and draining lymph nodes.

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An immunological correlation between the ancho ring filam ents of initial lym ph vessels and the neighboring elastic fibers: a unified mor phofunctional concept

The structure of the peritoneum has been studied by scanning and transmission electron microscopy and by light microscopy in 38 biopsies of 22 patients undergoing CAPD. Before CAPD the mesothelium was characterized by flattened cells with protruding nuclei, numerous microvilli and many pinocytotic vesicles. After prolonged CAPD there is a reduction and subsequent disappearance of microvilli and a vacuolar separation of cells from the basement membrane, accompanied by widening of intercellular junctions. Neither ultrafiltration rate nor small solute clearance change with these structural alterations. During peritonitis there is extensive cellular necrosis with denuding of the basement membrane. After recovery the mesothelium is replaced by thick fibrous connective tissue.

Pucci Am

Papers

Morphology of the peritoneal membrane during continuous ambulatory peritoneal dialysis.

Cholinergic and adrenergic innervation of mesenterial lymph vessels in guinea pig

An immunological correlation between the ancho ring filam ents of initial lym ph vessels and the neighboring elastic fibers: a unified mor phofunctional concept

The Morphology of the Peritoneum in CAPD Patients

The distribution of “capsaicin-sensitive” nerve fibers in the lymphatic wall