Israel Medical Association Journal

Ubiquitin-proteasome degradation is a key cellular process involved in almost every aspect of cell life. According to the current concept, proteins are stable unless they are marked by poly-ubiquitination for degradation by the 26S proteasomes. A new twist in the concept became evident while studying the degradation of the tumor suppressor p53, a protein that appeared to satisfy this principle. We have discovered that native p53 is also prone to ubiquitin-independent 20S proteasomal degradation, suggesting that certain proteins are inherently unstable. We further found that this process of degradation is mediated by 20S proteasomes and inhibited by NADH quinone oxidoreductase 1. Our recent findings together with previous observations of ubiquitin-independent degradation suggest the existence of ubiquitin-independent mechanisms for proteasomal protein degradation in the cells.

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.

Background: In the last decade there has been an increase in asthma morbidity. Hospital admission rates for childhood asthma are influenced by the prevalence of asthma and the quality of asthma care.

Objective: To assess trends in hospital admission and readmission rates for childhood asthma in the Jezreel Valley in Israel in the last decade, and to evaluate the possible effect of changes in asthma treatment upon hospitalization for acute asthma during this period.

Methods: All records from pediatric patients from the central hospital in the Jezreel Valley in northeastern Israel over a 10 year period from 1990 through 1999 who were diagnosed as having asthma were thoroughly reviewed and analyzed for admissions, re-admissions, and treatment before and during admissions

Results: There were 1584 admissions, 1208 were first-time admissions and 374 were re-admissions. The number of first-time admissions increased significantly over time (P < 0.0001), with a significant decrease of re-admissions (P < 0.005); this finding was more significant in children under the age of 8 years (P < 0.005). The length of hospital stay decreased significantly from 3.3 days to 2.7 days (P < 0.002). Significant changes in the use of medications included an increase in inhalant glucocorticoids and a decrease in the use of sodium cromoglycate and theophylline. Controller medication use was concomitant with a significant decrease in the re-admission rates.

Conclusions: The increase in the admission rate and the decrease in the rate of re-admissions and the length of hospital stay probably reflect the increase in the prevalence of asthma and changes in its treatment, respectively. It is essential that asthma be recognized as a significant cause of morbidity and that controller medications be administered to decrease the asthma's severity, morbidity, and resultant hospital admissions.
 

Background: Food allergies in children are often very serious and can lead to anaphylactic reactions. Observations that camel milk ameliorates allergic reactions were noted over the years. The effect of the camel milk is probably related to its special composition.

Objectives: To investigate the effect of camel milk in several children with severe food (mainly milk) allergies.

Methods: We studied eight children with food allergies who did not benefit from conventional treatment. Their parents, or their physicians, decided to try camel milk as a last resort. The parents were advised by the authors – who have considerable experience with the use of camel milk – regarding how much and when the children should drink the milk. The parents reported daily on the progress of their children.

Results: All eight children in this study reacted well to the milk and recovered fully from their allergies.

Conclusions: These encouraging results should be validated by large-scale clinical trials.

Background: Bladder exstrophy is a severe congenital defect that requires a multidisciplinary treatment approach. Soft tissue repair may be successful during the first few days after birth but a combination of pelvic osteotomies and bladder reconstruction is necessary later in life. The combination of externally fixed anterior and posterior osteotomies has biomechanical advantages over previous techniques for achieving primary bladder closure.

Objectives: To describe our experience with a combined vertical and horizontal pelvic osteotomy approach for the repair of bladder exstrophy.

Methods: Four children underwent bladder exstrophy closure; the mean age at surgery was 19 months (range 9–33 months)... We stabilized the osteotomies with a small Synthes AO external fixator, 4.0 mm rod diameter.

Results: All four patients had successful bladder repair with no dehiscence; two of them achieved partial continence, and bladder neck reconstruction is planned for the other two. Three of the four patients sustained neurologic injury; two completely recovered, and the third continues to suffer from right drop foot. The average follow-up was 39 months (range 10–60 months).

Conclusions: Vertical and horizontal pelvic osteotomies stabilized by external fixator and bladder repair is an effective treatment for bladder exstrophy.

Background: Advances in surgical techniques and retractor-stabilizer devices allowing access to all coronary segments have resulted in increased interest in off-pump coronary artery bypass. The residual motion in the anastomotic site and potential hemodynamic derangements, however, render this operation technically more demanding.

Objectives: To evaluate the OPCAB[1] experience in a single Israeli center.

Methods: Between 2000 and 2003 in our institution, 1,000 patients underwent off-pump operations. Patients were grouped by the type of procedure, i.e., minimally invasive direct coronary artery bypass or mid-sternotomy OPCAB.

Results: One hundred MIDCAB[2] operations were performed. Of the 900 OPCAB, 767 patients received multiple grafts with an average of 2.6 ± 0.6 grafts per patient (range 2–4) and the remaining patients underwent single grafting during hybrid or emergency procedures. In the multiple-graft OPCAB group, complete revascularization was achieved in 96%. Multiple arterial conduits were used in 76% of the patients, and total arterial revascularization without aortic manipulation, using T-graft (35%) or in situ configurations, was performed in 61%. The respective rates for early mortality, myocardial infarction and stroke in the MIDCAB were 1%, 0% and 2%, and 2%, 1.3% and 0.9% in the multiple-vessel OPCAB groups. Multivariate analysis identified renal dysfunction (odds ratio 11.5, confidence interval 3.02–43.8; P < 0.0001) and emergency operation (OR[3] 8.74, CL[4] 1.99–38.3; P = 0.004) as predictors of mortality. The proportion of off-pump procedures increased from 9% prior to the study period to 59%.

Conclusions: The use of OPCAB does not compromise the ability to achieve complete myocardial revascularization. Our procedure of choice is OPCAB using arterial conduits, preferably the 'no-touch' aorta technique.

Background: Hyperthermia combined with radiation therapy was shown to be more effective in local recurrent breast cancer than radiotherapy alone, but it use is limited due to technical difficulties, stringent reimbursement policies and because it is time consuming.

Objectives: To report our experience with a simple and convenient XRT+HT[1] delivery system.

Methods: XRT was delivered through either electron or photon beams (total dose 30–40 Gy in previously irradiated fields or 50–70 Gy in non-irradiated fields). Hyperthermia was delivered by a dedicated HT device operating at 915 MHz. The heating session lasted 45 minutes. The maximal tumor surface temperature was set at 45°C and modified according to patient comfort. No intratumoral (invasive) thermometry was used. At least two HT sessions were scheduled to each HT field during the entire XRT treatment period. Tumor response was evaluated every 3 months after completion of treatment. The overall survival was measured from XRT+HT initiation until the last follow‑up.

Results: Fifteen women underwent 114 HT treatments delivered through 28 HT fields. Twenty-four HT fields (15 patients) were previously irradiated. There was complete infield response in 10 fields (6 patients), partial response in 8 fields (4 patients), no response or progressive disease in 4 fields (3 patients), and no parameters in 6 fields (5 patients). Eighteen (64%) fields had complete or partial response. Seven patients had outfield recurrence despite wide XRT+HT fields. Ulceration was the only major side effect (three patients, three fields).

Conclusions: The combined HT+XRT delivery system, with no invasive thermometry, is a simple and effective method for treating local recurrent breast cancer.

Background: Several in vitro studies have reported on the efficacy of combined liposomal encapsulated doxorubicin (Doxil® or Caelyx®, MedEquip, UK) and hyperthermia over Doxil alone.

Objectives: To document the beneficial effect of Doxil-HT over Doxil alone in mice and to investigate the length of time HT[1] should be delivered.

Methods: M/109 lung tumor cells were injected into both leg pads of Balb/c female mice at age of 6–7 weeks. Two weeks later i.v. Doxil in a dose of 8 mg/kg (20–25 µg per mouse) was given and 4 HT sessions (2–3 days apart) were delivered during the subsequent 2 weeks at 2–3 days apart. HT was given to the left pad only for either 5 or 30 minutes (HT5 and HT30 respectively). Five weeks after tumor injection the mice were sacrificed and tumor volume and weight in both pads were measured. Internal comparisons between mice in the same treatment group and comparisons between different treatment cohorts were performed.

Results: In the combined Doxil-HT5 and Doxil-HT30 cohorts the tumor volume and weight in both pads were similar and did not differ from those achieved by Doxil alone. In the Doxil-HT30 cohort the tumor weight, but not the tumor volume, were smaller than those in Doxil-HT5 and Doxil alone (P = 0.006 and 0.01 respectively).

Conclusions: The combined Doxil-HT30 treatment is more effective then Doxil-HT5 or Doxil alone. Additional studies with different time scheduling and different temperatures are warranted.

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[1] HT = hyperthermia

Background: During a period of 13 months - 1 October 2000 to 31 October 2001 – 586 terror assault casualties were treated in the trauma unit and emergency department of Hadassah University Hospital (Ein Kerem campus); 27% (n = 158) were hospitalized and the rest were discharged within 24 hours.

Objectives: To analyze the special requirements of a large number of victims who received treatment during a short period.

Methods: Data were attained from the main admitting office and the trauma registry records. Analysis was conducted of: age, gender, mechanism of injury, anatomic site of injury, Injury Severity Score (ISS), and length of stay.

Results: Males comprised 81% of the hospitalized patients. The majority of the injuries (70%) were due to gunshot wounds and 31% of the hospitalized patients were severely injured (ISS ≥ 16). Twelve patients died, yielding a mortality rate of 7.5%.

Conclusion: The nature of the injuries was more complex and severe than trauma of other etiologies, as noted by the mean length of stay (10.2 vs. 7.2 days), mean intensive care unit stay (2.8 vs. 0.9 days), and mean operations per patient (0.7 vs. 0.5). The mean insurance cost for each hospitalized terror casualty was also higher than for other trauma etiologies (US$ 3,200 vs. 2,500).