Israel Medical Association Journal

Background: Leptin, a pleiotropic hormone, has been suggested to be part of an acute phase response during an inflammatory stimulus. Its correlation with other acute phase reactants during minor infection in children has not been investigated.

Objectives: To study the correlation between serum leptin levels to those of C-reactive protein, a well-documented acute-phase reactant, in a series of pediatric patients with acute minor infections.

Methods: Leptin and CRP[1] levels were measured in 62 blood samples of pediatric patients presenting with mild febrile illness who were admitted to Dana Children’s Hospital in Israel. All children were finally diagnosed as having minor infection based on the negative blood/urine cultures and favorable outcome.

Results: Serum leptin level was positively correlated with CRP (r² = 0.5), total white blood cells (r² = 0.33) and absolute neutrophil count (r² = 0.31). The regression coefficient was the highest between leptin and CRP.

Conclusions: Circulating leptin concentrations are positively correlated with CRP levels during acute minor infection in children visiting the emergency room for febrile illnesses. Our observation suggests that leptin is indeed a part of acute-phase proteins. The wide scattering showed that it is not a better marker in minor infections than CRP, but it may contribute to weight loss and anorexia seen in the minority of patients during mild infections.

Objectives: To study the necessity of bone marrow examination for the diagnosis and clinical course of MGUS[1].

Methods: We retrospectively screened the medical records of all patients in whom monoclonal protein was found in the serum during 2001–2002 in the medical laboratories of Sapir Medical Center. Asymptomatic patients who had serum monoclonal immunoglobulin G < 3.0 g/dl or IgA[2] < 2.0 g/dl or IgM < 1.0 g/dl without anemia, renal failure, hypercalcemia or any bone lesions on skeletal survey were eligible. Full records of patients who were evaluated in the hematology clinic were available (group 1). The remaining patients were followed by their family physicians; thus we had access only to their electronic files including laboratory results and new diagnoses (group 2). Demographic and clinical parameters as well as clinical course were evaluated.

Results: Both groups (57 and 255 patients, respectively) had similar demographic, laboratory and clinical characteristics. Bone marrow examination was performed in 30 of 57 patients (group 1): 16 were normal, 8 had an excess of normal plasma cells, and 6 had excess of pathologic plasma cells. However, only in two of the latter six could a diagnosis of multiple myeloma be established. All group 1 patients were followed for 22 ± 11 months and only two developed overt multiple myeloma. During the same period, 6 of 255 patients (group 2) were diagnosed as multiple myeloma and 3 as MGUS in other hospitals. The rest had a stable course with no change in their laboratory values.

Conclusions: Our findings suggest that bone marrow examination should not be performed routinely in patients who fulfill strict clinical and laboratory criteria of MGUS.

Objectives: To investigate and compare the epidemiologic, clinical and laboratory characteristics of cancer and non-cancer patients hospitalized with venous thromboembolism in a large referral medical center in Israel.

Methods: Between February 2002 and February 2003, patients diagnosed at the Rambam Medical Center as suffering from VTE[1] (deep vein thrombosis and/or pulmonary embolism), based on diagnostic findings on Doppler ultrasonography, spiral computed tomography scan or lung scan showing high probability for pulmonary embolism, were prospectively identified and evaluated. In addition, at the conclusion of the study period, the reports of spiral chest CT scans, performed during the aforementioned period in this hospital, were retrospectively reviewed to minimize the number of unidentified cases. Blood samples were drawn for evaluation of the coagulation profile.

Results: Altogether, 147 patients were identified and 153 VTE events diagnosed, accounting for 0.25% of all hospitalizations during the study period. The cancer group included 63 patients (43%), most of whom had advanced disease (63%). The most common malignancies were cancer of the lung (16%), breast (14%), colon (11%) and pancreas (10%). Of 121 venous thromboembolic events (with or without pulmonary embolism) there were 14 upper extremity thromboses (12%). The most common risk factors for VTE, except malignancy, were immobilization (33%), surgery/trauma (20%) and congestive heart failure (17%). There was no difference in prevalence of various risk factors between cancer and non-cancer patients. During an acute VTE event, D-dimer levels were higher in cancer patients than non-cancer patients (4.04 ± 4.27 vs. 2.58 ± 1.83 mg/L respectively, P = 0.0550). Relatively low values of activated protein C sensitivity ratio and normalized protein C activation time were observed in both cancer and non-cancer groups (2.05 ± 0.23 vs. 2.01 ± 0.33 and 0.75 ± 0.17vs. 0.71 ± 0.22, respectively). These values did not differ significantly between the groups.

Conclusion: The proportion of cancer patients among patients suffering from VTE was high. Their demographic, clinical and laboratory characteristics (during an acute event) were not different from those of non-cancer patients, except for higher D-dimer levels.

Objectives: To test whether an early change in neurohormonal and inflammatory markers after implantation can predict the clinical response to CRT.

Methods: The study group included 32 patients with advanced symptomatic systolic heart failure and a prolonged QRS complex and who were assigned to undergo CRT. Baseline plasma levels of B-type natriuretic peptide and high sensitivity C-reactive protein were determined in the peripheral venous blood and coronary sinus. Post-implantation levels were determined 2 weeks post-procedure in the PVB[2]. Baseline levels and their change in 2 weeks were correlated with all-cause mortality and hospitalization for congestive heart failure.

Results: At baseline, coronary sinus levels of BNP[3] but not hsCRP[4] were significanly elevated compared to the PVB. Compared to baseline levels, BNP and hsCRP decreased significantly within 2 weeks after the implantation (BNP mean difference 229.1 ± 102.5 pg/ml, 95% confidence interval 24.2–434, P < 0.0001; hsCRP mean difference 5.2 ± 2.4 mg/dl, 95% CI[5] 0.3–10.1, P = 0.001). During a mean follow-up of 17.7 ± 8.2 months 6 patients died (18.7%) and 12 (37.5%) were hospitalized due to exacerbation of CHF[6]. Baseline New York Heart Association and CS[7] BNP levels predicted CHF-related hospitalizations. HsCRP levels or their change over 2 weeks did not predict all-cause mortality or hospitalizations.

Conclusions: BNP levels in the CS and peripheral venous blood during biventricular implantation and 2 weeks afterwards predict cilinical response and may guide patient management.

Polyubiquitylation of cellular proteins has long been recognized as a prelude to a degradative fate in proteasomes. In recent years, however, ubiquitin conjugation has emerged as a regulatory strategy of considerable versatility. Most notably, monoubiquitylation is attributed an intimate role in trafficking of membrane proteins between various cellular compartments. Diverse classes of transmembrane proteins from across the eukaryotic spectrum (e.g., epidermal growth factor-receptor and other receptor tyrosine kinases) become modified with monoubiquitin molecules. Monoubiquitylation of substrates, in turn, regulates both their endocytosis at the plasma membrane and sorting in endosomes for delivery to lysosomes or vacuoles. A mechanistic rationale lies in the identification of a growing list of ubiquitin-binding domains carried by a variety of endocytic adaptor proteins. Thus, ubiquitin-conjugated membrane proteins may form extensive contacts with the endocytic machinery. Further, ubiquitin-binding adaptors and other endocytic components are, likewise, often monoubiquitylated. In this case, ubiquitin conjugation may serve to enhance intermolecular avidity in cargo-bound endocytic complexes, or alternatively, to mediate timely inactivation of ubiquitin-binding adaptors. Interestingly, the ubiquitin/endocytosis interface is appropriated by pathogenic organisms, for instance, during budding of viruses from host-infected cells. Moreover, compromised ubiquitin-mediated transport of certain signaling receptors is associated with disease states, including oncogenic transformation.

We describe a unique E3, the F-box protein, Ufo1, of yeast. Ufo1 recruits the mating switch endonuclease, Ho, to the SCF complex for ubiquitylation. In addition to the F-box and WD40 protein-protein interaction domains found in all F-box proteins, Ufo1 has a unique domain comprising multiple copies of the ubiquitin-interacting motif. Ufo1 interacts with the UbL-UbA protein, Ddi1, via its UIMs[1], and this is required for turnover of SCF ^Ufo1 complexes. This is a novel function for an UbL-UbA protein. Deletion of the genomic UFO1 UIMs is lethal and our data indicate that Ufo1ΔUIM acts as a dominant negative leading to inhibition of the SCF pathway of substrate degradation and to cell cycle arrest. Furthermore, we found that Ddi1 is required for the final stages of degradation of Ho endonuclease. In the absence of Ddi1, Ho does not form a complex with the 19S RP and is stabilized. Stabilization of Ho leads to perturbation of the cell cycle and to the formation of multi-budded cells. Our experiments uncover a novel role for the ubiquitin-proteasome system in maintenance of genome stability.

In this issue of IMAJ, two articles discuss and review the roles of chronic airway infection (1) and inflammation (2) respectively in cystic fibrosis lung disease.

Background: Heat shock proteins are highly conserved immunodominant antigens found in various species. Humoral immune responses to mycobacterial HSP65[1] and human HSP60 have been established in a number of human autoimmune diseases.

Objective: To assess the prevalence of antibodies to HSP60 kDa and HSP65 kDa in patients with Sjogren's syndrome as compared to normal subjects.

Methods: Thirty-seven patients with SS[2] were compared with normal controls. The antibodies against human HSP60 were measured by the Anti-Human (IgG/IgM) HSP60 ELISA kit. IgGs[3] and IgMs to mycobacterial HSP65 were determined using an enzyme-linked immunosorbent assay with mycobacterial recombinant HSP65 antigens.

Results: The levels of both anti-HSP60 and -HSP65 were lower among patients compared with controls. IgG autoantibodies to HSP60 were significantly different between groups: 162 ± 55.1 ng/ml in controls versus 112.3 ± 30.6 ng/ml in SS patients (P < 0.001). The levels among controls of anti-HSP65 IgM isotype were also significantly higher than among patients: 111.6 ± 33.4 U/ml versus 96.1 ± 8.9 U/ml (P = 0.01).

Conclusions: The results of the present study show that the levels of different isotypes of anti- HSP60 and HSP65 antibodies were lower in patients with SS than in normal subjects. Additional studies on larger patient populations are required to evaluate the prevalence of these autoantibodies in SS patients.

Objectives: To describe the role of wireless capsule endoscopy in diagnosing isolated small intestinal Crohn’s disease in two adolescents.

Methods: Wireless capsule endoscopy was performed in two adolescents with severe protein-losing enteropathy and negative standard diagnostic workup.

Results: Wireless capsule endoscopy successfully diagnosed Crohn’s disease with uncharacteristic presentations and negative radiographic and endoscopic findings in both patients.

Conclusions: The non-invasiveness and ease in performance of capsule endoscopy on an ambulatory basis make this diagnostic modality especially advantageous for children.

The ubiquitin-proteasome pathway has a central role in selective degradation of intracellular proteins. Among the key proteins degraded by the system are those involved in the control of inflammation, cell cycle regulation and gene expression. With numerous important cellular pathways affected, derangements in the ubiquitin system were shown to result in a variety of human diseases including malignancies, neurodegenerative diseases and hereditary syndromes, and proteasome inhibition was implicated as a potential treatment for cancer and inflammatory conditions. Two proteasome inhibitors are currently under clinical evaluation for multiple myeloma and acute ischemic stroke. The ubiquitin system also has an important function in the immune and inflammatory response. It is involved in antigen processing and presentation to cytotoxic T cells, and the activation of nuclear factor-kappa B – the central transcription factor of the immune system. Since the proteasome is the central source of antigenic peptides that are presented to the immune system, some viruses, such as the Epstein-Barr virus, developed escape mechanisms that manipulate the ubiquitin-proteasome system in order to persist in the infected host. Understanding the mechanisms underlying the production of viral antigens by the ubiquitin-proteasome system may have therapeutic applications such as future development of vaccines.