Israel Medical Association Journal

Background: Health care workers bear the risk of both contracting influenza from patients and transmitting it to them. Although influenza vaccine is the most effective and safest public health measure against influenza and its complications, and despite recommendations that HCWs[1] should be vaccinated, influenza vaccination coverage among them remains low.

Objectives: To characterize influenza vaccination coverage and its determinants among employees in an Arab hospital in Israel.

Methods: An anonymous, self-administered questionnaire was distributed among employees involved in patient care in the winter of 2004–2005 at Nazareth Hospital in Israel. The questionnaire included items related to health demographic characteristics, health behaviors and attitudes, knowledge and attitude concerning influenza vaccination, and whether the respondent had received the influenza vaccine during the previous winter or any other winter.

Results: The overall rate of questionnaire return was 66%; 256 employees participated in the study. The immunization coverage rate was 16.4%, similar to that reported for other hospitals in Israel. Logistic regression analysis demonstrated a significant association only between influenza vaccination coverage and the presence of chronic illness and influenza vaccination in the past.

Conclusions: Influenza vaccination coverage among Nazareth Hospital health care workers was low. They did not view themselves as different to the general population with regard to vaccination. An intervention program was launched after the study period, aimed at increasing the knowledge on the efficacy and safety of the vaccine, stressing the importance of vaccinating HCWs, and administering the vaccine at the workplace. The program raised the vaccination coverage to 50%.

Background: Osler taught that splenic infarction presents with left upper abdominal quadrant pain, tenderness and swelling accompanied by a peritoneal friction rub. Splenic infarction is classically associated with bacterial endocarditis and sickle cell disease.

Objectives: To describe the contemporary experience of splenic infarction.

Methods: We conducted a chart review of inpatients diagnosed with splenic infarction in a Jerusalem hospital between 1990 and 2003.

Results: We identified 26 cases with a mean age of 52 years. Common causes were hematologic malignancy (six cases) and intracardiac thrombus (five cases). Only three cases were associated with bacterial endocarditis. In 21 cases the splenic infarction brought a previously undiagnosed underlying disease to attention. Only half the subjects complained of localized left-sided abdominal pain, 36% had left-sided abdominal tenderness 31% had no signs or symptoms localized to the splenic area, 36% had fever, 56% had leukocytosis and 71% had elevated lactate dehydrogenase levels. One splenectomy was performed and all patients survived to discharge. A post hoc analysis demonstrated that single infarcts were more likely to be associated with fever (20% vs. 63%, p < 0.05) and leukocytosis (75% vs. 33%, p = 0.06)

Conclusions: The clinical presentation of splenic infarction in the modern era differs greatly from the classical teaching, regarding etiology, signs and symptoms. In patients with unexplained splenic infarction, investigation frequently uncovers a new underlying diagnosis. 

Mesenchymal stem cells, or mesenchymal stromal cells, have emerged as a major new cell technology with a diverse spectrum of potential clinical applications. MSCs[1] were originally conceived as stem/progenitor cells to rebuild diseased or damaged tissues. Over the last 14 years, since the first report of MSC infusions in patients, the cells have been shown to suppress graft vs. host disease, stimulate linear growth in a genetic disorder of bone, and foster engraftment of haplo-identical hematopoietic stem cells. In all cases, few, if any, MSCs were identified at the site of clinical activity. This experience suggests a remarkable clinical potential, but a different general mechanism of action. Systemically infused MSCs seem to exert a therapeutic effect effect through the release of cytokines that act on local, or perhaps distant, target tissues. Rather than serving as stem cells to repair tissues, they serve as cellular factories that secrete mediators to stimulate the repair of tissues or other beneficial effects. Since both the tissue source of MSCs and the ex vivo expansion system may significantly impact the cytokine expression profile, these parameters may be critically important determinants of clinical activity. Furthermore, cell processing protocols may be developed to optimize the cell product for a specific clinical indication. For example, MSC-like cells isolated from placenta and expanded in a three-dimensional bioreactor have recently been shown to increase blood flow in critical limb ischemia. Future efforts to understand the cytokine expression profile will undoubtedly expand the range of MSC clinical applications.

Mesenchymal stromal cells are multipotent cells capable of tissue repair and immune modulation. They are primarily found in bone marrow, but are also present in other tissues of mesenchymal origin, such as fatty tissue, muscle, tendons, etc. MSC[1] can easily be obtained by bone marrow aspiration, showing a rapid expansion in vitro. New protocols enable cell culture without the use of animal-derived sera and artificial growth factors. Avascular necroses of the bone may have different causes. AVN[2] in autoimmune and hematological diseases show a strong association with corticosteroid treatment, which is often unavoidable in severe cases. Until recently, core decompression of the affected osseous area was the standard approach. Because of their differentiation properties, easy accessibility and proliferative capacity, autologous MSCs could potentially complement AVN treatment by adding fresh “osteogenic cells” to the healing process.

The Ink4a-Arf locus, which encodes two distinct tumor suppressor proteins, is inactivated in many cancers. Whereas p16^Ink4a is an inhibitor of cyclin D-dependent kinases, p19^Arf (p14^ARF in humans) antagonizes the E3 ubiquitin protein ligase activity of Mdm2 to activate p53. We now recognize that Arf functions in both p53-dependent and -independent modes to counteract hyper-proliferative signals originating from proto-oncogene activation, but its p53-independent activities remain poorly understood. Arf proteins are highly basic (> 20% arginine content, pI > 12) and predominantly localize within nucleoli in physical association with an abundant acidic protein, nucleophosmin (NPM/B23). When bound to NPM[1], Arf proteins are relatively stable with half-lives of 6–8 hours. Although mouse p19^Arf contains only a single lysine residue and human p14^ARF has none, both proteins are N-terminally ubiquitinated and degraded in proteasomes. Through as yet uncharacterized mechanisms, p19^Arf induces p53-independent sumoylation of a variety of cellular target proteins with which it interacts, including both Mdm2 and NPM. A naturally occurring NPM mutant (NPMc) expressed in myeloid leukemia cells redirects both wild-type NPM and p19^Arf to the cytoplasm, inhibits Arf-induced sumoylation, and attenuates p53 activity. Thus, ubiquitination and sumoylation can each influence Arf tumor suppressor activity.

Background: Experimental and clinical protocols are being developed for the cryopreservation of human hematopoietic progenitor cells. However, the effect of these procedures on the potential for HPC[1] to repopulate bone marrow is unknown.

Objectives: To examine the effect of cryopreservation on the ability of fetal human liver HPC, which include CD34+ cells and long-term culture-initiating cells, to repopulate immunodeficient non-obese diabetic/severe combined immunodeficiency mouse bone marrow.

Methods: Groups of sublethally irradiated NOD[2]/SCID[3] mice were injected intravenously with cryopreserved or freshly isolated fetal human liver HPC.

Results: Seven weeks after transplantation, flow cytometric analysis of bone marrow samples showed that mice that received the transplanted cells (either cryopreserved or freshly isolated) demonstrated both lymphoid and myeloid differentiation as well as the retention of a significant fraction of CD34+ cells. Conclusions: Cryopreserved fetal human liver-derived HPC appear to be capable of initiating human cell engraftment in NOD/SCID mouse bone marrow and open the possibility of using cryopreserved fetal human liver HPC for gene manipulation, gene transfusion therapy, and transplantation purposes.

_______________________________

[1] HPC = hematopoietic progenitor cells

[2] NOD = non-obese diabetic

[3] SCID = severe combined immunodeficiency

Background: Chronic childhood autoimmune hemolytic anemia is an uncommon disorder that is associated with significant morbidity. Treatment with high dose steroids, splenectomy and frequent blood transfusions results in a myriad of complications including growth failure, bone demineralization, Cushing’s syndrome, immunosuppression, and transfusional hemosiderosis.

Objectives: To investigate the efficacy of the monoclonal anti-CD20 antibody, rituximab, in treating children with AIHA[1].

Methods: Four children with chronic AIHA, including two with prior splenectomy, who were dependent on high dose steroids and refractory to other immunosuppressive regimens were treated with four to six weekly doses of rituximab at a dose of 375 mg/m².

Results: All four patients became transfusion-independent and were taken off prednisone completely. Adverse effects included infusion-related reactions that were mild, and infectious complications of Pneumocystis carinii pneumonia and varicella pneumonia.

Conclusions: Treatment with rituximab appears promising for refractory AIHA; it may obviate the need for prednisone and may result in sustained disease remissions in some patients.