תוצאת חיפוש

בן-עמי סלע

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

החשיבות של יציבות המירקם החוץ-תאי (extracellular matrix, להלן EMC) בשמירת שלמות דופן כלי הדם מוכרת היטב, בין השאר מהבנת מחלות בהן נפגעת שלמות EMC, כמו לדוגמה בתיסמונת Marfan. כשמעלים את נושא ה- EMC, מוזכרת בנשימה אחת קבוצת אנזימי המירקם נושאי האבץ, MMP, בשל חשיבות פעולתם הפרוטאוליטית בפירוק של רוב המרכיבים החלבוניים במירקם האמור. על חשיבותם האבולוציונית של אנזימי MMP תעיד העובדה, שעד היום זוהו 66 אנזימים כאלה החל ביצורים ירודים כמתגים מסוימים, ועד לאדם, בו התגלו עד כה 21 אנזימים ממשפחה זו. במקביל נתגלו  4 חלבוני ריקמה (tissue inhibitors of MMP, או TIMP), היוצרים קשר לא-קוולנטי עם האנזימים האמורים ומנטרלים את פעולתם. אנזימי MMP מופרשים כזימוגנים בלתי-פעילים אנזימית, ושיפעולם נעשה באמצעות פרוטאינאזות אחרות כפלסמין, טריפסין ולפחות MMP ממברנתי אחד שכינויו –MT-MMP, המבקעים פפטיד קצר בזימוגן, ומביאים להתמרתו ל- MMP פעיל. בסקירה קודמת בעיתון זה, ייחדנו מקום לחשיבותם של אנזימי המירקם הללו בתהליך הסרטני, ואילו בסקירה הנוכחית יורחב הדיון למשמעויות של אנזימי MMP בהיבטים אחדים של כלי הדם.
 

Antioxidant Profile of Human Saliva and its Biological Significance

R. M. Nagler, A. Z. Reznick

Dept. of Oral and Maxillofacial Surgery, Salivary Clinic and Oral Biochemistry Laboratory; Rambam Medical Center and Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa

Saliva is the first biological medium to come in contact with materials entering the body through the oral cavity. These materials are contained in food and drink (or inhaled as volatile ingredients). Accordingly, saliva contains various defense mechanisms which have been thoroughly investigated. They include immunological and enzymatic systems aimed at pathological microorganisms. Saliva also can protect the mucosa against mechanical insults and when required, promote its healing via agents such as the epidermal growth factor.

Another defense mechanism in saliva which has been gaining increased attention and seems to be of paramount importance is its antioxidant system. We discuss both the molecular and enzymatic components of the salivary antioxidant system in respect to mixed, parotid, submandibular and sublingual saliva and under various physiological conditions of secretion.

Prematurity: Interplay between Psychological and Biological Risk Factors Leading to Infant Psychopathology

Miri Keren, Galia Tyano, Leah Sirota

Community-based Infant Mental Health Unit, Geha Hospital; Sackler School of Medicine, Tel Aviv University; Kibbutz Seminar, Ramat Aviv; Neonatal Intensive Care Nursery, Schneider Children's Hospital, Petah Tikva; and Sackler School of Medicine, Tel Aviv University

Concepts such as risk factor, vulnerability, protective factor and resiliency have become central in the field of developmental psychopathology. The birth of a very-low-birth weight premature baby can be used as a paradigm of the interplay between these factors. Indeed, prematurity implies for both infant and parents, biological as well as psychological risk factors. They may interact in such a way that the child's emotional, cognitive and social development will deviate from normal. Understanding the psychological impact of premature birth includes reference to both the normal psychological processes that characterize pregnancy that are jeopardized by a premature, often traumatic delivery, and to the special significance of being a parent in the Special Care Nursery.

The contrast between the expected appearance of the baby and that of the sick-looking, tiny premature, together with uncertainty about its medical status, often affect the parents' bonding process. In addition, must learn quickly to cope with issues such as total dependence on a verybusy team, loss of control of the care of their baby, and their unclear roles as parents. Added to these risk factors are the specific neurobehavioral characteristics of premature babies, which often make it hard for parents to read their cues and respond to them properly.

A clinical vignette illustrates the chain of psychological and biological events that lead to severe disturbance of the early parent-child relationship. It also brings up the question of psychosocial intervention in the Special Care Nursery, both in terms of early detection of families at risk and the types of intervention.

Irritable Bowel Syndrome: Biofeedback Treatment

N. Barak, R. Ishai, E. Lev-Ran

Biofeedback Unit, Psychiatric Ward, Sheba Medical Center, Tel Hashomer

Irritable bowel syndrome is a group of heterogenic complaints of functional bowel disorder in the absence of organic pathology. The pathophysiology is unclear. In most cases treatment includes symptomatic remedies, antidepressants, psychotherapy and hypnotherapy.

Biofeedback has recently been introduced as a therapeutic modality. Treatment also includes relaxation techniques and guided imagery, together with computer-assisted monitoring of sympathetic arousal. Biofeedback requires active participation of patients in their healing progress and leads to symptom reduction in 2/3.

Irradiation Injury of the Salivary Glands

R. M. Nagler

Dept. of Oral and Maxillofacial Surgery and Oral Biochemistry Laboratory, Rambam Medical Center and Technion Faculty of Medicine, Haifa

Ionizing irradiation of the salivary glands often leads to severe histological and functional alterations. Such exposure usually occurs during radiotherapy in patients with head and neck malignancy. The consequent xerostomia, often life-long, may result from even relatively low dosage irradiation, and causes a great deal of suffering. We suggest a radiobiological mechanism for this phenomenon which has been studied extensively since first described in 1911. The suggested injurious role of redox active transition metal ions and highly destructive free radicals is discussed in relation to the ultimate radiosensitive cellular target, DNA.

Nasopharyngeal Colonization with Streptococcus Pneumoniae in Pediatric Respiratory Infections

Isaac Srugo, Irena Chystiakov, Ella Cohen, Yoram Tal, Michael Jaffe

Clinical Microbiology and Pediatric Depts., Bnai Zion Medical Center and Technion Faculty of Medicine, Haifa

During the winter of 1995, nasopharyngeal colonization of Streptococcus pneumoniae was evaluated in 204 children with respiratory infection and 107 normal control children. There was no difference in gender or mean age between the groups, and no difference in carrier rate between sick (24.5%) and normal (22%) children (p=0.6). Carrier rates were 19%, 32%, 31% and 17% at 6, 12, 24 and 48 months, respectively. Penicillin-resistant pneumococci (PRP) were found in 42% of sick and 16.6% of normal children, (p<0.05). Resistance to more than 2 antibiotics was found in 28% of sick and in 12.5% of normal children. PRP were found in 67% and 34% of sick children with and without prior antibiotic treatment (p<0.05). We conclude that there is no difference in the carrier rate of Streptococcus pneumoniae between sick and normal children. However, the high prevalence of PRP in children with respiratory infections is probably due to prior antibiotic treatment.

Aseptic Loosening of Joint Implants

Dror Fuchs, Chaim Zinman, Dina Lewinson

Orthopedic and Traumatology Dept. B, Rambam Medical Center; and Div. of Morphology Sciences, Bruce Rappaport Faculty of Medicine, The Technion, Haifa

The purpose of orthopedic joint implants is to improve joint movement. Within the past 30 years, biomechanical improvements affecting the life-span of the implants has brought a new type of problem: the biological response to debris from the implant material contributes greatly to aseptic loosening of the prosthesis. The process is mediated by osteotropic factors, cytokines released from mononuclear cells, and osteoblasts and osteoclasts in the bone-cement interface or bone-implant interface.

Onchocerca in Israel

A. Pressman, Y. Kandelis, Y. Bachar, G. Mogilner

Depts. of Pediatric Surgery and Pathology, Bnei-Zion Medical Center and Bruce Rappaport Faculty of Medicine, The Technion, Haifa

The parasite Onchocerca volvulus is well-known in its endemic areas in South and Central America and West Africa. It is transmitted to man by simulium flies and causes systemic infection with skin, lymphatic and ophthalmic manifestations and can cause blindness (river blindness). Treatment with Ivermectin is effective but sometimes there is need for surgical intervention to prevent or treat complications. We describe an 11-year-old girl, a new immigrant from Ethiopia, who had a firm mass in her left thigh, caused by Onchocerca volvulus. It was completely excised. This is a very rare condition in Israel, which must be considered in patients coming from endemic areas.

Fungus-Ball in a Preterm Infant Successfully Treated with Fluconazole

Mirit Hershman-Sarafov, Orora Tubi, Isaac Srugo, David Bader

Neonatal and Radiology Depts., and Microbiology Laboratory, Bnai-Zion Medical Center and Bruce Rappaport Faculty of Medicine, The Technion, Haifa

Very-low-birth-weight premature infants are at high risk for invasive candidiasis. The most commonly involved organ is the kidney. Renal candidiasis may present as fungus-ball obstructive uropathy. We describe unilateral renal obstruction secondary to fungus-ball in a premature infant. Noninvasive, systemic antibiotic treatment, including amphotericin B and fluconazole, resulted in disappearance of the finding.

Conservative Approach in Children with Central Line Infection 

Zvi Steiner, Yafim Kandelis, George Mogilner, Dina Atias, Isaac Srugo

Dept. of Pediatric Surgery, and Hematology and Clinical Microbiology Units, Bnei-Zion Medical Center, and Bruce Rappaport Faculty of Medicine, The Technion, Haifa

In 1994-1995, central venous lines were placed in 47 children. All except 1 were of the Broviac type, with subcutaneous tunneling via the internal or external jugular vein. Ages were between 7 days and 16 years. Indications for central venous cannulation were chemotherapy (35 cases), TPN (5), prolonged parenteral antibiotics (4), and repeated blood transfusions (3). The catheter was the source of infection in 13 children (28%), 11 of whom were immunocompromised. The commonly identified bacteria were Staphylococcus aureus (4 cases), Pseudomonas aeruginosa (4), coagulase-negative Staphylococcus (2), and various gram-negative rods (3). All cases were treated with antibiotics through the catheter. The most commonly used were oxacillin (4), ceftazidime (4), and amikacin (4). In 10, treatment succeeded without having to remove the line. In 2 others, tunnel infection developed and the catheter had to be removed. 1 child forcefully removed his catheter before treatment could be started. There were no further complications in the group treated conservatively, except for a case of superior vena cava thrombosis in a girl with recurrent infection of the tunnel. In 7 out of 13 treatment was continued and completed at home. This saved 65 days of hospitalization out of 210. We conclude that the conservative approach to treatment is feasible in most cases of infection when the source is the central venous catheter itself. However, when the tunnel is infected, conservative treatment may be ineffective. Treatment can be carried out in the home, with economy in cost and in use of hospital beds, and is preferred by patients and their parents.

Incidence, Antimicrobial Resistance and Mortality in Bloodstream Infections in the Critically Ill

Lavi Oud, Shelly Krimerman, Isaac Srugo

General Intensive Care Unit and Clinical Microbiology Dept., Bnai-Zion Medical Center, Haifa

Bloodstream infections (BSI) are 7-fold more common in patients admitted to the intensive care unit (ICU) rather than to other hospital wards. The epidemiology of BSI in critically ill patients in Israel has not been systematically addressed. We examined the annual trends in BSI in patients in a general ICU of evolving patterns of antimicrobial resistance and associated mortality rates for the years 1994-1996. The presence of the systemic inflammatory response syndrome (SIRS) when the first positive blood cultures are taken was a prerequisite for its definition as clinically significant. The unit site, staff, practice guidelines, and type of patient were unchanged during the study period. Blood cultures were positive in 220.7-332.0 patients per 1000 ICU admissions, 18-22-fold more common than in regular ward patients. SIRS was a universal finding in these ICU patients. There was multi-drug resistance for the majority of species cultured, reaching 100% in some cases. Crude hospital mortality of ICU patients, with and without positive blood cultures, was 31-54% and 5-14%, respectively. The introduction of a new blood culture system (Bactec 9240) in 1996 was associated with a 61% increase in the rate of patients with positive blood cultures, accounted for mostly by increased isolation of coagulase-negative staphylococci. However the mortality rate for the latter decreased by 59%, suggesting the possibility of a selective increase in detection of contaminated cultures. Although highly prevalent in the study population and generally defining a patient group with high mortality risk, the specificity of SIRS-associated positive blood cultures may be species and culture-system dependent. These findings re-emphasize the need for both improved control measures for the epidemic proportions of BSI and multi-drug antimicresistance, as well as more specific indicators of the clinicaof positive blood cultures in critically ill patients.

Biofeedback Treatment of Raynaud's Disease

M. Birger, R. Sha'anani, F. Pavlotzki

Psychiatric Day Care and Dermatology Depts., Chaim Sheba Medical Center, Tel Hashomer and Psychiatric Service of Leumit Health Insurance Company

Raynaud's disease is characterized by intermittent peripheral vasoconstriction leading to pallor, cyanosis and reactive vasodilation of the arterioles of fingers and toes. These phenomena are accompanied by sensations of cold or warmth, pain and difficulty in manipulating the palms. Ulcerations of the fingertips can occur in severe cases. Since conservative medical treatment, consisting of preventive measures and changing various habits, results in alleviation in only half the patients, sympathectomy is often required. Psychological intervention, including biofeedback, also has a significant role. Biofeedback involving relaxation techniques, guided imagination, and in parallel, computer-assisted monitoring of sympathetic arousal, might lead to symptom reduction as a unique treatment or in conjunction with other treatment modalities.

Biological Test for Menopausal Osteoporosis

Benjamin Klein, Nathan Rojansky

Depts. of Experimental Surgery and of Obstetrics and Gynecology, Hadassah- Hebrew University Medical Center, Ein Kerem, Jerusalem

Osteoporosis has become a major public health problem in many western countries in which about 25% of women by the age of 65 will have had osteopenic fractures. The most important contributing factor to this condition is loss of gonadal function. This progressive disease, characterized by reduction in bone mass, may be prevented by estrogen replacement therapy. While there are several methods of diagnosing the disease when already established, there is no method that can identify women at high risk of developing osteoporosis. We have developed a biological test in which the serum of postmenopausal women is added to rat osteoprogenitor cell culture and its influence on proliferation, differentiation and mineralization of bone cells is determined. The serum of 20 menopausal women was examined by the biological test and the results compared to the findings of dual photon absorptiometry. This showed that rapid bone-losers had a significantly lower mineralization index as compared to nonosteopenic women (p<0.0001). The proliferation index (cell count) and alkaline phosphatase activity did not show significant differences between osteopenic and nonosteopenic groups. This preliminary study showed that a test based on serum reacting with a culture of bone cells to induce mineralization may be of value in the diagnosis of osteoporosis.