תוצאת חיפוש

בן-עמי סלע

המכון לכימיה פתולוגית, מרכז רפואי שיבא, תל השומר, החוג לביוכימיה קלינית, הפקולטה לרפואה סאקלר, אוניברסיטת תל-אביב

הגילויים התכופים המתפרסמים לאחרונה על תאי הגזע (stem cells) מעוררים התרגשות של ממש. דורות שלמים התחנכו על העקרונות הקלאסיים של הביולוגיה ההתפתחותית, לפיהם ייעודם של תאים נקבע ונחתם בשלבים עובריים מוקדמים. על פי גישה מסורתית זו, תאים מוגבלים לרקמות ולאברי המוצא שלהם; לדוגמה, תאי גזע המאטופויאטיים הממוקמים בלשד-העצם, הם המקור לתאי דם שונים, אולם תאי גזע אותרו גם במעי, בבלוטות הרבייה, בעור ואף במוח. כיום מתברר והולך, שתאים בוגרים יכולים להיות מתוכנתים מחדש ולבטא גנים האופייניים למיגוון תאים שונים בתכלית שעברו התמיינות (differentiation) בכל אחת משורות התאים (lineage) העובריות: האנדודרמית, המזודרמית והאקטודרמית. התנאי ההכרחי ל"שינוי זהותו" של תא הגזע, הוא נדידתו לריקמת היעד הזרה, שם הוא קולט אותות כימיים ועובר התמרה לזהות תאית חדשה. גמישות (plasticity) מפתיעה זו של תאים בוגרים משמעותה, שגם לאחר התמיינותם, עשויים תאים מסויימים לשנות את ייעודם. בסקירה זו, מובאות דוגמאות אחדות להדגמת המהפך הבלתי-צפוי בזהותם של תאים.

Hemophagocytic Syndrome

I. Morag, M. Goldman, T. Bistrizer, C. Kaplinsky

Pediatric Division, Assaf Harofeh Medical Center, Zerifin and Pediatric Hematology-Oncology Dept., Chaim Sheba Medical Center, Tel Hashomer and Sackler Faculty of Medicine, Tel Aviv University

Hemophagocytic syndrome is a rare, fulminant disease characterized by generalized histiocytic proliferation associated with phagocytosis of erythrocytes, platelets, and to a lesser extent, of white blood cells. We report a 2-year-old boy admitted with high fever and irritability, with a rash, marked hepatomegaly and generalized lymphadenopathy. Liver function tests were abnormal and there was thrombocytopenia and hyperlipidemia. Bone marrow aspiration revealed hemophagocytosis. Despite intensive treatment with steroids, intravenous immunoglobulin and cytotoxic drugs, he died within 10 weeks.

Paroxysmal Nocturnal Hemoglobinuria

Haim Ben-Ami, Yehuda Edoute

Medical Dept. C, Rambam Medical Center and Bruce Rappaport Faculty of Medicine, The Technion, Haifa

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired disorder of blood cells which originate from an abnormal hematopoietic stem cell. The condition is characterized by nocturnal hemoglobinuria, chronic hemolytic anemia, and thrombosis. We describe a 60-year-old woman with PNH admitted with abdominal pain and jaundice, who had dark urine on arising after a night's sleep. The diagnosis was established by the typical clinical story and a positive Ham test. She was successfully treated with Halotestin and folic acid. Although PNH is rare, it should be considered in the differential diagnosis of hemolytic anemia. Early diagnosis and treatment are important.

Closed Intramedullary Nailing of Forearm Fractures in Young Patients

Moshe Salai, Eyal Segal, Yehuda Amit, Aharon Chechick

Dept. of Orthopedic Surgery, Chaim Sheba Medical Center, Tel Hashomer

Forearm bone fractures are commonly the result of falling on the outstretched hand or of direct injury. The preferred treatment is debated. The possible modalities are: application of a cast, often necessitating repeated manipulations; open reposition and fixation by plates and screws; or closed manipulation and closed intramedullary nailing. We present our favorable results in treating these fractures in young patients by closed intramedullary nailing, and compare them with the unfavorable results of this method in mature adults.

Identification of Sentinel and Axillary Node Involvement in Breast Cancer

M.Z. Papa, D. Bersuk, M. Koler, E. Klein, M. Sareli, G. Ben-Ari

Dept. of Surgical Oncology and Breast Unit, Chaim Sheba Medical Center, Tel Hashomer

Axillary node dissection for breast cancer is important for staging and prognosis. "Sentinel nodes" are the first nodes into which primary cancer drains. Identification, removal and pathological examination of those nodes indicates whether completion of axillary lymphadenectomy is required. The sentinel nodes are identified using a vital dye injected at the primary tumor site. With this technique we were able to identify sentinel nodes in 46 of 48 (95%) women examined. An average of 2.7‏1.2 nodes were identified as sentinel nodes. In 81% of cases there was a correlation between involvement of sentinel nodes and of other axillary nodes as well. In 10% of patients sentinel nodes were involved with tumor while other axillary nodes were negative. The major problem in routine application of this is relationship in surgical decisions is reliable real time pathological identification of lymph node involvement by tumor.