Israel Medical Association Journal

Mixed cryoglobulinemia is a systemic vasculitis described as a triad characterized by purpura, weakness and arthralgias. Since the first description of the disease in 1964 by Meltzer and Franklin our understanding of its pathogenesis has increased considerably. The striking association of the disease with hepatitis C virus infection was initially noted in 1990. Since then, the disease has gained growing attention among investigators involved in the study of autoimmune systemic disorders because it represents one of the most intriguing models of autoimmunity triggered by a virus. Nonetheless, a number of answered questions still remain to be resolved and are reviewed in this article.

Between the 1960s and 1980s, the main focus of biological research was nucleic acids and the translation of the coded information into proteins. Protein degradation was a neglected area and regarded by many as a scavenger, non-specific and end process. While it was known that proteins are turning over, the large extent and high specificity of the process - where distinct proteins have half-lives that range from a few minutes to several days - have not been appreciated. The discovery of the lysosome by Dr. Christian de Duve did not change this view significantly, as this organelle is involved mostly in the degradation of extra- and not intracellular proteins, and it was clear that lysosomal proteases, similar to those of the gastrointestinal tract, cannot be substrate specific. The discovery of the complex cascade of the ubiquitin pathway has changed this view dramatically. It is now clear that degradation of cellular proteins is a highly complex, temporally controlled, and tightly regulated process that plays major roles in a broad array of basic pathways during cell life and death. With the multitude of substrates targeted and processes involved, it is not surprising that aberrations in the pathway have been recently implicated in the pathogenesis of many diseases, certain malignancies and neurodegeneration among them. Degradation of a protein via the ubiquitin pathway involves two successive steps: a) conjugation of multiple ubiquitin moieties to the substrate, and b) degradation of the tagged protein by the downstream 263 proteasome complex with release of free and re-utilizable ubiquitin. Despite intensive research, the unknown still exceeds what we currently know on intracellular protein degradation and major key problems remain unsolved. Among these are the modes of specific and timed recognition of the myriad substrates of the system and the nature of the mechanisms that underlie aberrations in the system and pathogenesis of diseases.

Background: Hepatitis B is a major problem worldwide. Israel has intermediate endemicity for hepatitis B virus, and an annual carrier rate of 1-3%.

Objective: To evaluate both the prevalence of HBV infection among family members of HBV carriers and the competence of family practitioners in performing a compre­hensive assessment.

Methods: A total of 152 HB surface antigen-positive blood donors were discovered in our subdistrict during the years 1993-97. Their family physicians were questioned regarding the patients' family members. Specific information on 85 spouses and 200 children was also obtained.

Results: Among the 85 married carriers, 5 of the spouses (5.9%) were found to be HBsAg positive. None of the 200 children was HB5Ag positive. We found that in a third (n=52) of the patients, the sexual partner had never been tested by a primary care physician. Patients were not routinely tested for HB e antigen or anti-HBe antibodies. Neither the parents nor the siblings had undergone any serological evaluation. How­ever, most family members of the carriers had received an HBV vaccine from their family physicians.

Conclusions: Our findings show that horizontal transmis­sion of HBV among spouses of HBV carriers still exists. We did not find any vertical transmission, probably due to male predominance and previous vaccination. Family physicians should be trained to perform an extensive serological evalua­tion of family members of patients with chronic HBV infection, including parents and siblings, and should vaccinate sero­negative family members.

Background: Patients who feel involved in their treatment have better outcomes than those who do not.

Objective: To identify determinants of perceived patient involvement in obstetric care.

Methods: A retrospective study was undertaken in 1,452 (83%) of 1,750 women sampled in November 1995 from maternity wards of 14 general hospitals in Israel. A postal and telephone survey using a self-administered questionnaire included the following variables: hospital (identity number), patients' age, self-reported complications, previous deliveries, education, ethnicity, and number of obstetric interventions performed and/or considered. The main outcome measured was the reported involvement in decisions for obstetric interventions.

Results: Reported full involvement varied from 72% for epidural analgesia to 13% for forceps/vacuum extraction. Factor analysis identified two dimensions of perceived involvement: one for routine” interventions (enema, monitor­ing, IV line and episiotomy), which are performed in Israel mostly by midwives, and another for "special" interventions (forceps/vacuum extraction, epidural or other analgesia, and cesarian section) performed by physicians. Logistic regression identified hospitals, younger age, number of interventions, and Arab ethnicity as correlates of a perceived non-involvement in decisions for "special" interventions.

Conclusions: Clinical setting, age and ethnicity affected patient perception of involvement in decisions for obstetric interventions.

Background: Recent genetic susceptibility findings in Jews of Eastern European descent, commonly called Ashke­nazi Jews, have led to concerns that they may be stigmatized as being more cancer prone than other groups.

Objective: To examine the hypothesis that site-specific or all-cancer incidence and mortality rates are higher than expected in Ashkenazi Jews worldwide when compared with referent populations.

Methods: A MEDLINE search was performed using keywords "Jews", "cancer", "incidence" and "mortality" to identify studies directly relevant to the primary study question.

Results: Little evidence suggested that all-cancer inci­dence or mortality is higher in Ashkenazi Jews than in North American non-Hispanic whites. Ashkenazi Jewish men appear to have relatively low cancer rates, which may be due to lower tobacco use. Colorectal cancer was shown to disproportio­nately overburden Ashkenazi Jews, who may also be at increased risk for ovarian, pancreatic and stomach cancer, and non-Hodgkin’s lymphoma. Little evidence was found support­ing an elevated risk of breast cancer in Ashkenazi Jewish women. Rates of lung, cervical, penile and prostate cancers appear low in this population. Rate disparities were generally attributed to lifestyle differences, particularly diet and tobacco use, rather than to genetic predisposition.

Conclusions: Ashkenazi Jews do not appear to have a higher total cancer burden than comparable North American populations. Any cancer rate differentials in this group are more likely to be related to lifestyle and dietary factors than to genetics. However, colorectal cancer rates in Ashkenazi Jews may be the highest of any ethnic group in the world and cancer controllers should consider this when developing future screening, diagnostic and policy strategies.

Background: Case-control and prospective studies indicate that an elevated plasma homocysteine level is a powerful risk factor for atherosclerotic vascular diseases. Certain medications can induce hyperhomocystinemia, such as methotrexate, trimethoprim and anti-epileptic drugs. There are few reports indicating an interaction between lipid-lowering drugs (cholestyramine and niacin) and homocysteine. Recently, an interaction was shown between fenofibrate and benzafibrates (a fibric acid derivative) and homocysteine plasma levels.

Objectives: To evaluate the effects of different fibrates on plasma homocysteine levels and to measure the reversibility of this effect.

Methods and Results: We investigated the effects of ciprofibrate and bezafibrate on homocysteine levels in patients with type IV hyperlipidemia and/or low high density lipoprotein levels. While a 57% increase in homocysteine was detected in the ciprofibrate-treated group (n=26), a 17% reduction n homocysteine was detected in the group treated with bezafibrate (n=12). The increase in homocysteine in the ciprofibrate-treated group was sustained for the 12 weeks of treatment and was partially reversible after 6 weeks of discontinuing the ciprofibrate therapy.

Conclusions: These results indicate that an increase In plasma homocysteine levels following administration of flbrates is not a class effect, at least in its magnitude. Moreover, it is reversible upon discontinuation of the treatment.
 

Background: Alkaline tide is the transient increase in blood and urine pH following stimulation of gastric acid secretion. It is attributed to HC0₃ release from parietal cells in parallel with H+ secretion. The enzyme carbonic anhydrase is thought to be responsible for HC0₃ production from CO₂ and 0H in the parietal cell.

Objective: To examine the effect of pretreatment with the carbonic anhydrase inhibitor, acetazolamide, on the alkaline tide phenomenon.

Methods: Ten patients with dyspepsia and demonstrable alkaline tide were tested on three separate days. The pH and base excess were determined in arterialized venous blood before and 45 minutes after an intramuscular injection of pentagastrin. The pH of the urine was measured before and 120 mm after pentagastrin injection. Measurements were performed after pentagastrin alone on day 1 following pretreatment with acetazolamide 60 mm before pentagastrin on day 2, and after the administration of acetazolamide alone on day 3.

Results: Following the administration of pentagastrin alone, the blood base excess increased by 1.61 +0.2 mEq/L (mean + standard deviation) and the calculated alkaline tide at 45 mm was 33.99 ±4.49 mEq. On day 2 with prior adminis­tration of acetazolamide, base excess decreased by 0.21 + 0.39 mEq/L, and the calculated alkaline tide was -3.28±7.57 mEq, which was significantly lower than on day 1 (P=0 0001). On day 3, following acetazolamide alone, the base excess values decreased by 0.53~0.2 mEq/L and the alkaline tide was -10.05 +3.33 mEq there was no significant difference compared with day 2 (P= 0.44).

Conclusion: Pretreatment with acetazolamide abolished the alkaline tide induced by pentagastrin. This finding supports the view that carbonic anhydrase has a major role in the alkaline tide phenomenon.

Background: Classic Kaposi's sarcoma is a rare tumor with an indolent behavior. Local therapy is not applicable in disseminated cutaneous disease. Patients with advanced disease are usually treated with systemic chemotherapy.

Objectives: To assess the effectiveness and toxicity of  single-agent vinblastine in the treatment of disseminated and recurrent Kaposi's sarcoma.

Methods: Ten patients with wide cutaneous spread of classic Kaposis sarcoma were treated with single-agent vinblastine, 6 mg/m² intravenously once every 2 weeks. Vinblastine was continued for 2 months after achieving a maximal response.

Results: The male:female ratio was 2.3:1, and median age 64 years (range 50-79 years). The median number of involved nodules in the skin was 34. The overall response rate was 90%, 5 with complete response (50%) and 4 with partial response (40%). Complete responders had a longer duration of response than partial responders: 41.2 vs. 14.8 months. The median survival of all patients was 33 months. Side effects were minimal and tolerable.

Conclusions: Vinblastine is very effective in the treatment of extensive classic Kaposi's sarcoma, and results in a high response rate, long survival and disease-free survival with tolerable toxicity.

Background: Routine prenatal ultrasound has increased the frequency of prenatal diagnosis of congenital cystic lung malformation, such as cystic adenomatoid malformation, pulmonary sequestration, congenital lobar emphysema, and bronchogenic cyst.

Objectives: To evaluate the methods of postnatal diag­nosis, the optimal age for operation since surgery is always required, and the optimal extent of lung resection.

Methods: The clinical courses of 11 patients with congenital lung cysts who underwent surgical lung resection (8 lobectomies and 3 segmentectomies) were reviewed.

Results: The diagnosis was confirmed by computed tomography scan in all. In nine patients the diagnosis was made prenatally. Chest X-ray was normal postnatally in all patients except for two who had recurrent pneumonia. Post­operative follow-up showed excellent recovery in all operated children. One patient who underwent surgery for CCAM following episodes of severe pneumonia died from another cause 5 months later. Postoperative chest CT scan showed no residual disease in eight patients. In two who had undergone limited resection, tomography showed a small segment of residual disease in one and a suspected residual lesion in the other.

Conclusion: With prenatal ultrasound the true frequency of congenital cystic lung anomaly appears to be higher than previously reported. Postnatal CT is mandatory to confirm or to rule out the diagnosis. The mere presence of cystic lung malformation is an indication for surgery. Complete removal of the affected lung lobe is recommended. Segmental resection may be inadequate. Early operation is tolerated well by infants and small children and we recommend that surgery be performed in children between 6 and 12 months of age.