Enhanced thermal stability of lysosomal beta-D-galactosidase in parenchymal cells of tumour bearing mice

The thermal stability of the enzyme beta-D-galactosidase varies among different organs in normal C57Bl/6 mice, and increases in the same organs in mice with Lewis Lung carcinoma. Thermal stability of this enzyme is also increased by treatment of the mice with cell-free extracts of tumour cells or with inflammatory compounds such as carrageenan or orosomucoid. After desialylation, orosomucoid more effectively increases the heat stability of the enzyme. By contrast talc, which has no galactosyl groups, is without effect on the stability of the enzyme in vivo. Macrophages of tumour bearing mice release into the culture medium a more heat resistant enzyme than macrophages from control mice. In both cases the heat resistance of the secreted enzyme is higher when fetal calf serum is present in the culture medium. Bovine serum does not modify the thermal stability of beta-D-galactosidase in this system. Incubation of lysosomal fractions of various organs with the synthetic beta-D-galactosidase substrate, p-nitrophenyl-galactopyranoside, also strongly increases the heat resistance of the enzyme. The results suggest that one factor influencing the heat resistance of this enzyme may be complex formation between the enzyme and its substrates, an example of substrate protection of the enzyme. This may not be the only factor involved in enzyme stabilization in vivo.     

Correlation between skin prick test using commercial extract of cow''s milk protein and fresh milk and food challenges

The skin prick test (SPT) is regarded as an important diagnostic measure in the diagnostic work-up of cow's milk protein allergy. It is not known whether commercial extracts have any advantage over fresh milk. The aims of the study were to (i) compare the diagnostic capacity of SPTs for the three main cow's milk proteins (alpha-lactalbumin, casein and beta-lactoglobulin) with fresh milk and (ii) determine a cut-off that discriminates between allergic and tolerant children in a controlled food challenge. A study was carried out on 104 children consecutively attending two paediatric allergy clinics for suspected cow's milk allergy. A clinical history, SPTs with fresh cow's milk and commercial extracts of its three main proteins and a challenge test were performed on all the children. A study of the validity of the prick test was also performed by taking different cut-off points for fresh milk and its proteins. Twenty-eight of 104 challenge tests (26.9%) were positive. At a cut-off point of 3 mm, fresh milk showed the greatest negative predictive value (98%), whereas casein showed the greatest positive predictive value (PPV, 85%). Calculation of 95% predicted probabilities using logistic regression revealed predictive decision points of 12 mm for lactalbumin, 9 mm for casein, 10 mm for beta-lactoglobulin and 15 mm for fresh cow's milk. We found that the greater the number of positive SPTs for milk proteins, the more likely the positive response to challenge. Having a positive SPT for all three milk proteins had PPV of 92.3% and would seem more clinically useful than any cut-off. Both fresh milk and cow's milk extract of the three main proteins could be useful in the diagnostic work-up of cow's milk allergy. Finding positivity to all three cow's milk proteins seems to be a simpler and more useful way of avoiding oral food challenges.     

Increased QT variability in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy

Background and purpose: Although sudden death (SD) accounts for numerous cases of premature mortality in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), the risk factors responsible for this dramatic event remain unclear. We sought possible differences in the QT variability index (QTVI) – a well‐known index of temporal dispersion in myocardial repolarization strongly associated with the risk of SD – between a group of patients with CADASIL and healthy controls. Methods: A total of 13 patients with CADASIL and 13 healthy volunteers underwent a 5‐min electrocardiogram recording to calculate the QTVI. All the patients also underwent a clinical assessment, including functional status by Rankin score, and a magnetic resonance imaging (MRI) brain scan for quantitative analysis of T2‐weighted (T2‐W) and T1‐weighted (T1‐W) lesion volume (LV). Results: Short‐term QT‐interval analysis showed significantly higher QTVI (P = 0.029) in patients than in controls. In patients, notwithstanding the limitations of the small sample size, QTVI also well correlated with T1‐W LV (r = 0.747, P = 0.003) and T2‐W LV (r = 0.731, P = 0.005). Conclusion: Because patients with CADASIL have increased temporal cardiac repolarization variability as assessed by QTVI, this mechanism could underlie these patients’ risk of SD. Whether this easily assessed, non‐invasive marker could be used to stratify the risk of malignant ventricular arrhythmias in patients with CADASIL and, possibly, to guide their therapeutic management warrants confirmation from larger prospective studies.     

Arachidonic acid-stimulated platelet tests: Identification of patients less sensitive to aspirin treatment

Serum thromboxane-B2 (TxB2), together with arachidonic acid (AA)-induced platelet aggregation, are, at the moment, the most used tests to identify patients displaying high on-aspirin treatment platelet reactivity (HAPR). Both tests are specific for aspirin action on cyclooxygenase-1. While the correlation between serum TxB2 assay and clinical outcome is established, data are conflicting with regard to aspirin treatment and a possible association with AA-stimulated platelet markers and clinical outcome. To understand such discrepancy, we performed a retrospective study to compare both assays. We collected data from 132 patients receiving a daily dose of aspirin (100?mg/day) and data from 48 patients receiving aspirin on alternate days. All Patients who received a daily dose of aspirin were studied for AA-induced platelet aggregation together with serum TxB2 levels and AA-induced TxB2 formation was also studied in 71 patients out of entire population. Consistent with recommendations in the literature, we defined HAPR by setting a cut-off point at 3.1?ng/ml for serum levels of thromboxane B2 and 20% for AA-induced platelet aggregation. According to this cut-off point, we divided our overall population into two groups: (1) TxB2?<?3.1?ng/ml and (2) TxB2?>?3.1?ng/ml. We found low agreement between such tests to identify patients displaying HAPR. Our results show that AA-induced platelet aggregation >20% identify a smaller number of HAPR patients in comparison with TxB2. A good correlation between serum TxB2 and arachidonic acid-induced TxB2 production was found (r?=?0.76619).     

Effect of the lactic acid bacterium Streptococcus thermophilus on stratum corneum ceramide levels and signs and symptoms of atopic dermatitis patients

A reduced amount of total ceramides could be responsible for functional abnormalities of the skin of atopic dermatitis (AD) patients. The ability of an experimental cream containing sonicated Streptococcus thermophilus to increase skin ceramide levels in healthy subjects has been previously reported. The aim of the present work was to investigate the effects of the topical administration of a S. thermophilus-containing cream on ceramide levels of stratum corneum from AD patients. A 2-week application of the cream, containing a sonicated preparation of the lactic acid bacterium S. thermophilus, in the forearm skin of 11 patients led to a significant and relevant increase of skin ceramide amounts, which could have resulted from the sphingomyelin hydrolysis through the bacterial sphingomyelinase. Moreover, in all patients the topical application of our experimental cream also resulted in the improvement of the signs and symptoms characteristic of AD skin (i.e. erythema, scaling, pruritus).     

Bacterial vaginosis and preterm delivery: an open question

OBJECTIVE: To evaluate the prevalence of bacterial vaginosis in a population of Italian pregnant women and to study its association with adverse pregnancy outcomes, particularly preterm delivery. STUDY DESIGN: After giving informed consent, 598 women were consecutively enrolled at their first prenatal visit (13-18 weeks of gestation). The presence of bacterial vaginosis was assessed by Gram's method at 13-18 weeks of gestation (early bacterial vaginosis) and at 28-32 weeks of gestation (late bacterial vaginosis). Univariate and multiple logistic regression models of analysis were used to assess the statistical significance of the data. RESULTS: Preterm delivery occurred in 14.7% of pregnant women positivefor bacterial vaginosis at theirfirst prenatal visit and in 6.9% of healthy women (OR 1.6, CI 1.07-2.51). In patients with bacterial vaginosis, preterm delivery occurred more often in the 36th week of gestation (78.6%). CONCLUSION: The presence of bacterial vaginosis at an early gestational age is associated with preterm delivery, although in the study population the condition did not seem to be related to great prematurity.     

Nitric oxide: emerging implications for headache mechanics

The involvement of nitric oxide (NO) in the pathophysiology of primary headaches was suggested by several authors during the last decade. Migraine, cluster headache, tension headache, and cervicogenic headache have been extensively studied on the basis of NO donor headache pain. Different mechanisms seem to be involved in the generation of pain in these clearly different clinical head pain disorders. NO could control all the mechanisms leading to head pain. In migraine NO is correlated with endothelial activation, in cluster headache with a brainstem unravelling of the on/off regulatory clocks, in cervicogenic headache with a cytokine-dependent pain, and in tension-type headache with a sensitization of pain pathways at the spinal/trigeminal level. The next natural frontier in the study of pain in primary headaches seems to be the functional study of the relationship between NO and the immune regulatory system. Received: 30 Devember 2000 / Accepted in revised form: 9 April 2001     

Cross-talk between NO and HMGB1 in lymphocytic thyroiditis and papillary thyroid cancer

The controversy on whether or not inflammatory infiltrates in chronic lymphocytic thyroiditis predispose to cancer, has now merged into a debate over the role of the inflammatory infiltrates. The question is how and why some cells become transformed and what factors allow them to spread and in some cases become invasive. Here, we show that the amount of inflammatory mediators such as nitric oxide (NO) and high mobility group Box 1 protein (HMGB1) produced in thyroiditis microenvironment increases in tumors and could be involved in the cellular transformation process. NO and HMGB1 are known to attract macrophages that would promote angiogenesis, matrix remodelling and suppression of an efficient immune response. Inflammatory infiltrates could increase the risk of papillary cancer in patients with autoimmune lymphocytic thyroiditis. Cytokines and soluble inflammatory mediators involved in cancer-related inflammation are not only a target for innovative diagnostic and therapeutic strategies but they also represent a future challenge for oncologists.