Israel Medical Association Journal

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.

Background: The role of prostatic fossa radiation as salvage therapy in the setting of a rising prostate-specific antigen following radical prostatectomy is not well defined.

Objectives: To study the efficacy and safety of pelvic and prostatic fossa radiation therapy following radical prostatectomy for adenocarcinoma.

Methods: A retrospective review of 1,050 patient charts treated at the Sheba Medical Center for prostate cancer between 1990 and 2002 identified 48 patients who received post-prostatectomy pelvic and prostatic fossa radiotherapy for biochemical failure. Two patients were classified as T-1, T2A-9, T2B-19, T3A-7 and T3B-11. Gleason score was 2–4 in 9 patients, 5–6 in 22 patients, 7 in 10 patients and 8–10 in 7 patients. Positive surgical margins were noted in 28 patients (58%) of whom 18 had single and 10 had multiple positive margins. Radiation was delivered with 6 mV photons using a four-field box to the pelvis followed by two lateral arcs to the prostatic fossa.

Results: At a median follow-up of 34.3 months (25th, 75th) (14.7, 51,3) since radiation therapy, 32 patients (66%) are free of disease or biochemical failure. Exploratory analysis revealed that a pre-radiation PSA[1] less than 2 ng/ml was associated with a failure rate of 24% compared with 66% in patients with a pre-radiation PSA greater than 2 ng/ml (chi-square P < 0.006).

Conclusions: For patients with biochemical failure following radical prostatectomy early salvage radiation therapy is an effective and safe treatment option.

Recent studies have implicated the dying cell as a potential reservoir of modified autoantigens that may initiate and drive systemic autoimmunity in susceptible hosts. The uridine-rich small nuclear ribonucleoprotein complex is a common target for autoantibodies present in the serum of patients with systemic lupus erythematosus and SLE[1]-overlap syndromes. Four modifications occurring in this complex during apoptosis have been described to date: the caspase-mediated cleavage of the U1-70K protein, the U1 RNA and the Sm-F protein, and the association with hyperphosphorylated SR proteins. In addition, the U1 snRNP[2] complex has been shown to translocate from its normal subcellular localization to apoptotic bodies near the surface of cells undergoing apoptosis. This redistribution might facilitate exposure of the modified components of the U1 snRNP complex to the immune system when the clearance of apoptotic cell remnants is somehow disturbed. The modifications in the U1 snRNP components during apoptosis might represent the initial epitopes to which an immune response is generated and may be the trigger for the production of autoantibodies to this complex in patients with SLE or SLE-overlap syndromes. Therefore, it can be hypothesized that the exposure of elevated levels of apoptotically modified U1 snRNP to the immune system of a genetically susceptible individual might lead to the breaking of immunologic tolerance towards the U1 snRNP complex.

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Background: Superantigens produced by Staphylococcus aureus and Streptococcus pyogenes are among the most lethal of toxins. Toxins in this family trigger an excessive cellular immune response leading to toxic shock.

Objectives: To design an antagonist that is effective in vivo against a broad spectrum of superantigen toxins.

Methods: Short peptide antagonists were selected for their ability to inhibit superantigen-induced expression of human genes for cytokines that mediate shock. The ability of these peptides to protect mice against lethal toxin challenge was examined.

Results: Antagonist peptide protected mice against lethal challenge with staphylococcal enterotoxin B and toxic shock syndrome toxin-1, superantigens that share only 6% overall amino acid homology. Moreover, it rescued mice undergoing toxic shock. Antagonist peptides show homology to a β-strand/hinge/a-helix domain that is structurally conserved among superantigens, yet remote from known binding sites for the major histocompatibility class II molecule and T cell receptor that function in toxic T cell hyperactivation.

Conclusions: The lethal effect of superantigens can be blocked with a peptide antagonist that inhibits their action at the top of the toxicity cascade, before activation of T cells occurs. Superantigenic toxin antagonists may serve not only as countermeasures to biologic warfare but may be useful in the treatment of staphylococcal and streptococcal toxic shock, as well as in some cases of septic shock.
 

Background: The bladder tumor antigen stat is a simple and fast one-step immunochromatographic assay for the detection of bladder tumor-associated antigen in urine.

Objectives: To evaluate the BTA[1] stat in non-bladder cancer patients in order to identify the categories contributing to its low specificity.

Methods: A single voided urine sample was collected from 45 patients treated in the urology clinic for conditions not related to bladder cancer. Each urine sample was examined by BTA stat test and cytology.

Results: The overall specificity of the BTA stat test was 44%, which was significantly lower than that of urine cytology, 90%. The false positive rates for BTA stat test vary among the different clinical categories, being highest in cases of urinary tract calculi (90%), and benign prostatic hypertrophy (73%). Exclusion of these categories from data analysis improved BTA stat specificity to 66%.

Conclusions: Clinical categories contributing to low BTA stat specificity can be identified, and their exclusion improves the specificity of this test.

Background: Previous studies have demonstrated myocardial salvage by basic fibroblast growth factor administration following chronic myocardial ischemia or acute myocardial infarction.

Objectives: To study the effect of bFGF[1] on left ventricular morphometry following coronary occlusion and reperfusion episode in rats.

Methods: bFGF (0.5 mg) or placebo was continuously administered for a period of one week using an implanted osmotic pump. Animals were sacrificed 6 weeks after surgery and myocardial cross-sections were stained with Masson-trichrome and with anti-proliferating cell nuclear antigen antibody.

Results: LV[2] area, LV cavity diameter, LV cavity/wall thickness ratio, and injury size were unchanged compared with control animals. Proliferating endothelial cells were significantly more abundant in injured compared with normal myocardium, but with no differences between animals treated or not treated with bFGF.

Conclusions: One week of systemic bFGF administration following coronary occlusion and reperfusion had no additional effect on LV geometry or cellular proliferation in rats.

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[1] bFGF = basic fibroblast growth factor

[2] LV = left ventricular

Background: Previous data showed that new recombi­nant hepatitis B virus vaccine, which contains the S-protein component of the HBV surface together with the Pre-S₁ and Pre-S₂, is considerably more immunogenic than a second-generation recombinant I-IBV vaccine.

Objectives:To compare the immunogenicity and safety of a novel recombinant HBV vaccine S1, Pre-S₁ and Pre-S₂ protein components of the hepatitis B surface antigen - Bio­TM

Hep^TM 10 לg dose, to a licensed vaccine containing only the S-protein component - Engerix-B, 20 לg dose.

Methods: A prospective randomized study included 524 adults - 260 in the Bio-Hep group and 264 in the Engerix-B group. Both vaccines were administered in a three-dose regimen given at 0, 1 and 6 months, and adverse events were recorded on a diary card 5 days after each vaccination. lmmunogenicity was tested by measuring anti-hepatitis B surface antibody.

Results: One month after the third injection, 98% of the BioHep^TM subjects were found to be seroprotected vs. 85.1% of the Engerix-B group. In addition, the geometric mean titers were 2,203 mlU/ml and 326 mlU/ml in the Bio-Hep-B and Engerix-B groups respectively. An immunogenic advantage of Bio-Hep-B was suggested by the rapid onset of antibody response - 66.5% were seroconverted one month after the first injection as compared to 19.3% in the Engerix-B group. No unexpected adverse events were observed, and the recorded events were mild in both groups.

Conclusions: BioHepTM, a novel recombinant HBV vaccine containing 5, Pre-S₁ and Pre-S₂ protein components. at a lower dose, is safe and more immunogenic than the conventional HBV vaccine that contains only S protein.

Anti-neutrophil cytoplasm antibodies are important markers of certain small vessel necrotizing vasculitides, but the optimal use of laboratory results in daily clinical practice necessitates collaboration between clinicians and laboratory specialists. Physicians must familiarize themselves with ANCA tests in ANCA-related vasculitides as well as in differential diagnostic patient populations in order to define cutoff values. Indirect immunofluorescence with a consensus-agreed technique combined with standardized enzyme immunoassays is the modality for detecting the main SSV-associated ANCA specificities using cutoff values that can sufficiently distinguish SVV from non-SVV patients. The combined use of IF and direct EIA to demonstrate proteinase 3-ANCA and myeloper­oxidase-ANCA at significant levels leads to a very high diagnostic specificity towards SVV conditions such as Wegen­er’s granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome, and limited forms of these such as renal-limited focal necrotizing glomerulonephritis. A strong reactivity of ANCA against several azurophil granule components indicates a drug-induced syndrome. ANCA-related SVV and drug­induced vasculitis or lupus syndromes have characteristic ANCA profiles that can help distinguish these conditions from other inflammatory diseases.

Background: The free-to-total prostate-specificantigen ratio is the best marker for optimizing prostate cancer detection. The main problem with studies of percent free PSA is the variability of reported cutoff values.

Objectives: To evaluate the influence of prostate size on the ratio of free to total PSA.

Methods: The study group included 58 patients (mean age 66.4 years) with clinically localized prostate cancer treated surgically at our institution. Total PSA and free PSA levels were measured by a solid phase enzyme immunoassay test (Hoffman-La Roche, Basel, Switzerland). The percent free PSA was compared with prostate size as determined from the surgical specimen.

Results: A direct relation was noted between prostate size and the percent free PSA value (r=0.49, P=0.0001). Mean percentage free PSA was 9%0.004 in men with normal-sized gland while in men with large prostate (60 g) the average percent free PSA was 15.90.09 (P=0.001).

Conclusions: In patients with prostate cancer the percent free PSA level is influenced by the gland size. The larger the prostate the higher the proportion of the free PSA. Such information may have influence on the recommendation for prostate biopsy in screening programs for early detection of prostate cancer.

Background: Previous studies have published controversial results regarding a connection between Helicobacter pylori infection and colorectal cancer. One possible mechanism is increased gastrin secretion in subjects infected with H. pylori, insofar as gastrin is known to be a trophic factor for the colonic mucosa.

Objectives: To investigate a possible role of gastrin secretion in H. pylori infection associated with colorectal cancer, and determine whether H. pylori infection is a factor in this disease.

Methods: The serum gastrin levels and the presence of H. pylori IgG antibodies were measured in 51 colorectal cancer patients and 51 control subjects. The cancer patients were also tested for carcinoembryonic antigen and CA 19-9.

Results: H. pylori IgG antibodies were found in the serum of 41 (80.4%) of the cancer patients compared to 32 (62.7%) of the control subjects (P=0.05). A significant correlation was found between CA 19-9 (γ=0.3432, n=49, P=0.01) and seropositive H. pylori IgG antibodies in the serum of the cancer patients (odds ratio 2.43, and 95% confidence limit 0.99-5.95), but none between CEA and H. pylori IgG antibodies nor between the serum gastrin level and the presence of colorectal cancer.

Conclusions: The results of this study indicate a significant association between seropositive H. pylori IgG antibodies and elevated CA 19-9 in colorectal cancer patients, but no correlation between the serum gastrin level and the presence of this cancer. H. pylori seropositivity is more prevalent in patients with colorectal cancer.