Nutations in growing plant shoots as a morphoelastic flutter instability.

Growing plant shoots exhibit spontaneous oscillations that Darwin observed, and termed 'circumnutations'. Recently, they have received renewed attention for the design and optimal actuation of bioinspired robotic devices. We discuss a possible interpretation of these spontaneous oscillations as a Hopf-type bifurcation in a growing morphoelastic rod. Using a three-dimensional model and numerical simulations, we analyse the salient features of this flutter-like phenomenon (e.g. the characteristic period of the oscillations) and their dependence on the model details (in particular, the impact of choosing different growth models) finding that, overall, these features are robust with respect to changes in the details of the growth model adopted. This article is part of the theme issue 'Topics in mathematical design of complex materials'.

QUS in monitoring raloxifene and estrogen-progestogens: a 4-year longitudinal study.

The aim of the study is to evaluate the effectiveness of phalangeal quantitative ultrasound (QUS) in monitoring the treatment with raloxifene or estrogen-progestogens in postmenopausal women attending an Italian Menopause Centre. Caucasian women (n = 268) were enrolled in the study and underwent annual check-ups between October 1998 and October 2004. All were measured with the IGEA DBM Sonic Bone Profiler (BP) at the startup of treatment and in the following years. Three groups were identified: subjects not receiving treatment (n = 144), subjects treated with raloxifene (n = 53) and subjects treated with estrogen-progestogens (n = 71). The three analyzed groups were similar for age, weight and menopausal age. A significant decrease in amplitude-dependent speed of sound (AD-SoS) and Ultrasound Bone Profile Index (UBPI; p < 0.05) was observed in the nontreated group, whereas a positive effect in treated groups could be evidenced in the follow-up. In particular, a significant positive effect (p < 0.05) on AD-SoS corrected for age in the group treated with raloxifene has been observed, whereas in the group treated with estrogen-progestogens a nonsignificant positive effect on AD-SoS corrected for age was observed. The absolute AD-SoS value was maintained over the years of follow-up. The UBPI data show a slowing down of the bone loss in the treated groups, especially in the raloxifene group, in contrast with the significant decrease in the nontreated group. The result of this study shows the DBM Sonic Bone Profiler is an efficient device to monitor the effects of treatment, not only in the strict control settings of clinical trials, but also in clinical practice.

Anti-actin IgA antibodies in severe coeliac disease.

Anti-actin IgA antibodies have been found in sera of coeliacs. Our aim was to define the prevalence and clinical significance of anti-actin IgA in coeliacs before and after gluten withdrawal. One hundred and two biopsy-proven coeliacs, 95 disease controls and 50 blood donors were studied. Anti-actin IgA were evaluated by different methods: (a) antimicrofilament positivity on HEp-2 cells and on cultured fibroblasts by immunofluorescence; (b) anti-actin positivity by enzyme-linked immuosorbent assay (ELISA); and (c) presence of the tubular/glomerular pattern of anti-smooth muscle antibodies on rat kidney sections by immunofluorescence. Antimicrofilament IgA were present in 27% of coeliacs and in none of the controls. Antimicrofilament antibodies were found in 25 of 54 (46%) coeliacs with severe villous atrophy and in three of 48 (6%) with mild damage (P < 0.0001). In the 20 patients tested, antimicrofilaments IgA disappeared after gluten withdrawal in accordance with histological recovery. Our study shows a significant correlation between antimicrofilament IgA and the severity of intestinal damage in untreated coeliacs. The disappearance of antimicrofilament IgA after gluten withdrawal predicts the normalization of intestinal mucosa and could be considered a useful tool in the follow-up of severe coeliac disease.

Type 1 autoimmune hepatitis: patterns of clinical presentation and differential diagnosis of the 'acute' type.

BACKGROUND: Autoimmune hepatitis (AIH) has three different presentations: chronic, acute and asymptomatic. AIM: To evaluate AIH presentation in Italian patients and investigate criteria that differentiate between acute-type AIH and acute viral hepatitis. DESIGN: Prospective observational study. METHODS: Eighty-six consecutive patients with type 1 AIH and 41 with acute viral hepatitis (controls) were studied. 'Acute' AIH was defined as recent-onset (<30 days) symptoms (jaundice and/or fatigue and/or fever) with marked alterations in serum liver tests; the 'asymptomatic' pattern as the occasional detection of liver abnormalities, and the 'chronic' pattern as the presence of signs and/or symptoms of long-lasting liver disease. RESULTS: Of 86 AIH patients, 59 (68%) presented with the chronic pattern, 22 (26%) with the acute pattern, and 5 (6%) were asymptomatic. 'Acute' patients had higher AST, ALT and bilirubin serum levels (p < 0.0001). No differences were detected with respect to age and serum levels of alkaline phosphatase, gamma-GT, albumin or gamma-globulin. All three groups had similar prevalences of moderate/severe (vs. mild) histological findings and liver cirrhosis. When compared with controls with acute viral hepatitis, 'acute' AIH patients were more often female (82% vs. 24%, p < 0.0001) and had higher serum gamma-globulin levels (26.9 vs. 13.4 g/l, p < 0.0001) and AST/ALT ratio (1.20 vs. 0.61, p < 0.0001). DISCUSSION: Although in Italy type 1 AIH patients usually present with a chronic pattern, some 25% have an acute presentation resembling that of viral hepatitis. 'Acute' AIH and viral hepatitis can be reliably differentiated by simple parameters such as gender, gamma-globulin serum levels and AST/ALT ratio.

Skin tests in the diagnosis of eruptions caused by betalactams.

The aetiologic evaluation of adverse cutaneous reactions to penicillins is still not an easy problem to solve. Skin testing is usually carried out intradermally with benzylpenicilloyl polylysine (BPO-PPL) and minor determinant mixture (MDM), but these are often unsuitable for the detection of sensitivity to betalactam antibiotics. 101 selected subjects, with different cutaneous reactions to betalactams and with a clinical history of positive challenge, were skin tested (patch test, prick test, intradermal test) with a standard betalactam series (amoxycillin, sodium penicillin G, ampicillin, bacampicillin, aztreonam, ceftriazone, BPO-PPL, MDM). 1 or more positive reactions to skin tests, mainly to intradermal tests, were observed in 47.5% of the subjects studied, especially in those with maculopapular eruptions, urticaria/angioedema and drug reactions caused by ampicillin and amoxycillin. Cross-sensitivity was demonstrated in 22.8% of cases and was due almost solely to the semisynthetic penicillins. Finally, to increase the yield in detecting positive patients, it is necessary that ampicillin and amoxycillin be tested in addition to major and minor determinants.

Effective education of adults with asthma who are allergic to dust mites.

The effects of supplementary computer instruction in house dust mite-avoidance measures on adherence to implementing measures, on home dust mite-allergen levels, and on symptomatology were investigated in 52 adult patients with mite-associated asthma. Twenty-six patients received conventional instruction (counseling and written instruction) and the other 26 patients received conventional plus 22 minutes of interactive computer-assisted instruction. Instructions were aimed at mite-avoidance measures. Pre- and postinstruction dust samples were collected, and adherence was monitored. All patients kept symptom diaries twice a day. Patients' progress was followed for 12 weeks, and all patients completed the study. Adherence, number of observed and self-reported mite-avoidance measures implemented after visit, was higher for the computer group (p = 0.023). The computer-instructed group achieved significantly lower levels of mite allergen in bedroom carpets (p = 0.004) with mean levels of mite allergen declining from 6.5 +/- 7.6 to 2.2 +/- 4.3 micrograms/gm of dust (two-site monoclonal antibody assays), whereas levels for the conventional-instructed group did not change. Moreover, by study weeks 9 and 10, the computer-instructed group was significantly less symptomatic (p = 0.033). Mean symptom scores for this group decreased from 12.4 to 7.7, compared with 16.4 to 14.3. Conventional instruction supplemented with computer instruction is suggested in mite education.