Meniscal abnormalities: prospective correlation of double-contrast arthrography and arthroscopy

In a prospective study conducted over a 12-month period, 30 patients underwent double-contrast arthrography of the knee followed by arthroscopic study. An 80% correlation rate was found between results. Arthrography had a higher rate of accuracy (93%) than arthroscopy (84%) and had a 7% false-positive and 0% false-negative rate. A commonly overlooked arthrographic sign--the triple-S or stuck sail sign--was 91% accurate in the prediction of meniscal tears. The complementary nature of the two examinations is discussed.     

An analysis of ultrafiltration during acute peritoneal dialysis in rats

Transport into and from the peritoneal cavity is effected through separate membranes. Peritoneal function is the sum of the contributions of these membranes. The peritoneal dialysis membranes are defined as intestinal viscera and mesentery, parietal lining membrane, and liver and diaphragm. The present study was undertaken to determine which of these membranes participate in ultrafiltration during peritoneal dialysis. Studies were performed in rats using a hypertonic (1200 mOsm/L) dialysate solution containing 5.6% glucose, 2.8% amino acid, and electrolytes. Both intact and eviscerated rats were studied. The experiments were repeated in animals whose diaphragms were fibrotic and densely adherent to liver. Preparation of the diaphragm did not impact upon ultrafiltration. Ultrafiltration in controls (54 vs. 56 ml with and without a fibrotic diaphragm respectively) and in eviscerated groups (44 vs. 45 ml with and without a fibrotic diaphragm respectively) were not significantly different. However, controls had significantly more ultrafiltration than did eviscerated animals (p less than 0.01). The parietal viscera accounted for 56-59% of the ultrafiltration. This study demonstrates that both the intestinal viscera and parietal walls participate in ultrafiltration.     

Effects of vitamin D3 and cyclosporin A on HgCl2-induced autoimmunity in Brown Norway rats

BACKGROUND.: Mercuric chloride (HgCl₂ induces a lymphoproliferative disorderand autoimmune glomerulonephritis in Brown Norway (BN) rats.This syndrome is the consequence of T cell-dependent polyclonalB cell activation and autoantibody production. We have previouslyshown that HgCl₂-induced autoimmune perturbations can be preventedin BN rats by the administration of cyclosporin A (CsA). Themost potent vitamin D₃ metabolite 1,25(OH)₂ D₃ (Vit D₃) sharescertain immunomodulatory properties with CsA. We therefore choseto compare the effects of Vit D₃ to those of CsA in BN ratstreated with HgCl₂ in order to establish whether Vit D₃ eitheralone or in combination with CsA can attenuate an autoimmunesyndrome in vivo. METHODS.: BN rats were treated with HgCl₂ according to a standard protocol.Subgroups of rats were also given CsA alone, Vit D₃ or syntheticanalogues of Vit D₃ alone, or combinations of both agents. Differentdoses and routes of administration were compared. The followingmarkers of disease activity were evaluated: mortality, peakproteinuria, serum IgE concentrations, and renal immunoglobulindeposition. RESULTS.: Disease activity was markedly attenuated in all rats treatedwith CsA alone. Vit D₃ and certain of its synthetic analoguesadministered alone also tempered the autoimmune process, butto a lesser extent than did CsA. The effect of CsA alone wasso potent, that no additive or synergistic effects could bedemonstrated when CsA was administered in combination with VitD₃. CONCLUSIONS.: Despite similar described immunomodulatory effects in vitro,CsA is clearly more effective than Vit D₃ in preventing HgCl₂autoimmune disease in BN rats. This suggests that there is adifference in the cellular targets of these two agents in vivo,and/or a difference in the potency with which HgCl2-triggeredimmune activation is suppressed.     

Mean lifetime of microtubules attached to nucleating sites.

A simple two-phase (cap; no cap) macroscopic model describing the kinetic behavior at a labile tip of a microtubule has been proposed [Hill, T. L. (1984) Proc. Natl. Acad. Sci. USA 81, 6728-6732]. In the model, a microtubule exists either in a slowly growing phase (first-order rate constant, alpha) characterized by the existence of a GTP-tubulin cap at the growing tip; or the same microtubule exists in a rapidly shrinking phase (first-order rate constant, beta), which is entered if/when the GTP-tubulin cap is lost through a fluctuation, thus exposing GDP-tubulin subunits, which constitute the body of the microtubule. Transition between the two phases--i.e., loss of a cap (first-order rate constant, k) or formation of a new cap (first-order rate constant, k') occurs very infrequently and in a stochastic manner. In vitro experiments with centrosome-nucleated microtubules by Mitchison and Kirschner and Monte Carlo kinetic simulations, based on a realistic set of microscopic rate constants that apply to the end of a microtubule, suggest this alternation between two "quasimacroscopic" phases. In this paper, I outline the calculation of the mean lifetime of a microtubule nucleated on a centrosome by using Hill's model. For a microtubule M units long in the slowly growing phase, the mean lifetime for complete depolymerization is [M(k + k') + alpha + beta](beta k - alpha k')-1, provided that beta k greater than alpha k'. If the microtubule is in the rapidly shrinking phase, then the mean lifetime is M(k + k')(beta k - alpha k')-1, provided that beta k greater than alpha k'. In case beta k less than alpha k', the microtubule grows indefinitely, and the mean lifetime is infinite.     

Patellofemoral joint: kinematic MR imaging to assess tracking abnormalities

The patellofemoral joint was imaged with magnetic resonance (MR) in the axial plane while the knee was positioned from 0 degrees to 32 degrees of flexion (nine positions). These multiple sequential images obtained within the early phases of flexion of the knee were viewed in a "cine-loop" format, producing a kinematic study that clearly demonstrated the relationship of the patella to the trochlear groove. Four healthy subjects and one patient with known bilateral subluxing patellae were studied. The preliminary results suggest that kinematic MR imaging of the patellofemoral joint is potentially useful for the evaluation of patellar tracking abnormalities.     

Second malignant tumors in patients with laryngeal carcinoma: diagnosis, treatment, and prevention

Although the survival rates reported for patients with larynx carcinoma are quite good, there is a risk of developing second malignant tumors (SMT) in this population. The prognosis for SMT is poor, particularly with tumors of the lung and esophagus. The Rochester series was analyzed for larynx stage and specific SMT sites, possible common etiologic factors, and survival of the population as a whole, as well as for the SMT group. From a total of 235 patients with larynx carcinoma and a median follow-up of 10 years, 50 patients with 61 SMT were identified. The overall incidence of developing a SMT was 21%, with 44% of the SMT in the lung. The median survival from SMT diagnosis was 8.74 months and the 2-year survival was only 26%. More than twice as many SMT were observed than would be expected in the population at risk, with an observed-to-expected ratio (OER) for lung SMT of 5.3, and 8 times as many head and neck SMT occurring in our population. These SMT are not treatment related but are most likely caused by a combination of exposure to a common carcinogen, that is, tobacco smoke and alcohol, and to inherent factors, notably "condemned mucosa syndrome." Follow-up procedures, from the perspective of SMT development in larynx cancer patients, are addressed in an attempt to improve survival. The focus of this study is the high incidence of lung primaries that could be mistaken for metastatic disease, which is relatively uncommon in early larynx cancer patients.     

Quality assurance problems in clinical hyperthermia and their impact on therapeutic outcome: a Report by the Radiation Therapy Oncology Group

Since February 1981, 300 patients with superficial measurable tumors were randomized on an RTOG protocol (81-04) involving fractionated radiation therapy (4.00 Gy twice weekly for a total of 32.00 Gy), either alone or followed immediately by hyperthermia (42.5 degrees C, 60 min). This is a report of 218 eligible patients with single lesions: 107 treated with radiotherapy alone (RT), 111 with radiotherapy plus hyperthermia (RT + HT). Only 56% of the 24 tumors less than 3 cm and 36% of the 53 lesions larger than 3 cm received what was felt to be "adequate" therapy (greater than or equal to 29 Gy and 8 heating sessions). Overall complete response (CR) was observed in 28% of the patients treated with RT, and 32% of the patients receiving RT and heat. Response has been found in previous analyses of this and other RTOG studies to be significantly related to both maximum tumor diameter (less than 3 or greater than or equal to 3 cm) and site/histology (breast/adenocarcinoma, head and neck/squamous, or other site/histologies). In the head and neck tumors less than 3 cm in diameter there was no difference in CR with irradiation alone or combined with hyperthermia (46% vs 43%). However, in the breast, and trunk and extremities a better CR rate was noted with irradiation and heat (55% and 67%) than with irradiation alone (33% and 0). In lesions less than 3 cm treated with irradiation and heat the probability of remaining in response was 80% compared with 15% with irradiation alone. In lesions larger than 3 cm no difference in CR was observed in either treatment group. It has been hypothesized that the response rate is higher in patients with smaller lesions (less than 3 cm) and in breast/chest wall, trunk/extremity lesions because these tumors and anatomical sites are easier to heat adequately. Problems encountered in correlating tumor response with quality of heating include less than optimal heating in larger lesions and the limited ability of current thermometry to accurately represent the temperature distribution in a tumor. Furthermore, differences in equipment and treatment practices among institutions add to the variability in heat administration data collected. In addition, tumor response may be difficult to judge because of short survival of some patients and occasionally rapid tumor regression that may cause necrosis which may be misinterpreted as persistent tumor.(ABSTRACT TRUNCATED AT 400 WORDS)     

Diagnosis of gastrointestinal stromal tumors: A consensus approach

As a result of major recent advances in understanding the biology of gastrointestinal stromal tumors (GISTs), specifically recognition of the central role of activating KIT mutations and associated KIT protein expression in these lesions, and the development of novel and effective therapy for GISTs using the receptor tyrosine kinase inhibitor STI-571, these tumors have become the focus of considerable attention by pathologists, clinicians, and patients. Stromal/mesenchymal tumors of the gastrointestinal tract have long been a source of confusion and controversy with regard to classification, line(s) of differentiation, and prognostication. Characterization of the KIT pathway and its phenotypic implications has helped to resolve some but not all of these issues. Given the now critical role of accurate and reproducible pathologic diagnosis in ensuring appropriate treatment for patients with GIST, the National Institutes of Health convened a GIST workshop in April 2001 with the goal of developing a consensus approach to diagnosis and morphologic prognostication. Key elements of the consensus, as described herein, are the defining role of KIT immunopositivity in diagnosis and a proposed scheme for estimating metastatic risk in these lesions, based on tumor size and mitotic count, recognizing that it is probably unwise to use the definitive term "benign" for any GIST, at least at the present time.