Photolysis and ozonolysis of (iso) desmosine-containing crosslinked peptides from porcine aorta elastin

This report describes the use of photolysis and ozonolysis as a means of achieving complete cleavage of the pyridinium ring of (iso)desmosine in crosslinked elastin peptides. Although photolysis leads to the opening of the ring with concomitant formation of lysine, the peptide chains remain attached. Subsequent ozonolysis is able to completely achieve the cleavage of the rest of the ring skeleton, thus leading to the separation of the peptide chains. Formation of new amino acids, i.e. α-aminoadipic and glutamic acids, is emphasized. Localization of these amino acids within the released peptides should be of help in structural investigations on the crosslinking zones involving either isodesmosine or desmosine. However, other amino acids such as tyrosine and phenylalanine are sensitive to this procedure and side reactions occur which are responsible for peptide bond cleavage with the formation of breakdown products.     

Sino-Atrial Dissociation: Evidence by Intracardiac Recordings in Man and by Microelectrode Studies on Isolated Rabbit Atrium

The electrophysiologic mechanisms of sinus dysfunction have recently been determined by direct recordings of the sinus node electrogram. The association of various degrees of abnormalities in the formation of the impulse within the sinus node and of sinoatrial conduction block, represents the pathophysiological substrate of the mechanism of sinus node dysfunction. The purpose of this work is to present clinical and experimental data supporting the concept of sinus node isolation. In our clinical case, the sinus node was probably intact despite aspects of sinus node dysfunction on the surface ECG. Sinus node electrograms were recorded with a sinoatrial conduction time of 100 ms (normal values in our laboratory: 83 ms +/- 38 ms). Atrial mapping demonstrated that the area depolarized by the sinus node involved a 2 cm2 zone surrounding it. This perisinusal activity could not be recorded on the surface ECG. Both exit and entry blocks in the sinus node were demonstrated. Our experimental data showed a total desynchronization between the electrical activity of the sinus node and that of the atrium under hypoxic conditions. Both types of cases demonstrated that an atrial dysrhythmia was coexisting with regular sinus activity. From these data we concluded that a sinus node free from any pathological involvement could be associated with severe symptoms of sinus node dysfunction on the surface ECG.     

Solubility of peptides in trichloroacetic acid (TCA) solutions Hypothesis on the precipitation mechanism

The assessment of proteolysis levels is often achieved by global quantification of the peptides soluble at different TCA concentrations, but little information is available on the features of this precipitation mechanism. Peptic, tryptic and chymotryptic digests of x_sl, β, and κ caseins have been prepared and fractionated by RP-HPLC and each isolated peptide was identified. Each digest was precipitated by adding TCA to different final concentrations (2, 4, 8, and 12%). The soluble fraction was analysed by RP-HPLC. Relationships have been searched between the properties of 75 peptides obtained in this way, and their solubilities in TCA. The best correlation was found with the peptide retention time in RP-HPLC, which can be regarded as the experimental measure of peptide hydrophobicity. We concluded that TCA, by interacting with peptides, induces an increase of the hydrophobicity of peptides which can lead to aggregation through hydrophobic interactions.     

Work hours,sleep patterns and fatigue among merchant marine personnel

SUMMARY A field study of work and sleep patterns among commercial merchant marine personnel is reported. Data collected over a 10-30-d period from 141 subjects aboard eight ships included information concerning work-rest schedules, sleep timing, alertness on the job and critical fatigue. The data indicate that watchstanders on the 4-on, 8-off schedule show considerable disruption in their sleep. The average sleep duration for all mariners is 6.6 h; watchstanders obtain their sleep in fragmented periods that are frequently less than 5 h in duration. Analysis of critical fatigue shows an incidence of 1-24% across personnel and measures. Of particular concern are the watchstanders on the 04.00-08.00 schedule, who sleep less than 4 h per 24-h period 22% of the time. Potential countermeasures, including changes in scheduling and staffing are proposed.     

COLLAGEN DISTRIBUTION IN FOCAL AND SEGMENTAL GLOMERULOSCLEROSIS: AN IMMUNOFLUORESCENCE AND ULTRASTRUCTURAL IMMUNOGOLD STUDY

Focal and segmental glomerulosclerosis (FSGS) is a non-specific scarring process of the glomerulus, initially described in idiopathic nephrotic syndrome. The distribution of types I, III, IV, V, and VI collagen and of the α 1, α 3, α 4, α 5, and α6 chains of type IV collagen was studied by immunohistochemistry in sclerotic lesions of nine nephrotic children. Dual immunofluorescence and high-resolution immunogold labelling were used to determine the precise distribution of the antigens. No changes were detected in normal glomeruli of patients compared with controls. In FSGS, type IV collagen [α 1(IV)2 α2(IV)], and to a lesser degree type VI, accumulates in the two components of the lesion: the enlarged mesangial matrix and the material deposited between the pushed-out podocytes and the α 3– α 5(IV)-positive glomerular basement membrane. Staining for α6(IV) and types I, III, and V collagen was practically negative. These results suggest that the matrix components of the sclerotic lesion are produced solely by glomerular cells. Changes in the relative distribution of type IV collagen chains, characterized by the presence of collagen [α 1(IV)2 α2(IV)] in close contact with the podocytes, strongly suggest a switch in the podocyte programme of collagen synthesis.     

Invasive reperfusion study II. Multicentre European randomized trial of anistreplase vs streptokinase in acute myocardial infarction

IRS II (Invasive reperfusion study II) was a multicentre randomizedtrial comparing the efficacy of a 2–5-min 30 U anistreplaseintravenous injection with a 1 500 000 U 60-min streptokinase(SK) intravenous infusion in acute myocardial infarction. 116patients were randomized within 6 h of onset of symptoms. Earlycoronary patency was assessable in 107 patients by coronaryangiogram performed 102 min after thrombolytic treatment (range:30–297 min) in the anistreplase group and 93 min (range:22–330 min) in the SK group. The early coronary patencyrate was significantly higher in the anistreplase group thanin the SK group: respectively, 70% (38/54) and 51% (27/53),P<0.05. Fifty patients had assessable coronary angiogramsat 90 min and 24 h. The 24-h patency rate was 92.3% (24/26)in the anistreplase group vs 87.5% (21/24) in the SK group.No early reocclusion occurred in the anistreplase group vs 15.4%(2/13) in the SK group (NS). Fibrinogen fell to 13.2 ±19.8%on anistreplase vs 9.4 ±10.3% on SK (NS). Bleeding complicationsoccurred in 12% (7/58) of treated patients in the anistreplasegroup vs 20.7% (13/58) in the SK group (NS). Two cerebrovascularaccidents occurred after thrombolytic treatment with anistreplase(3.4%) vs one after SK (1.7%) (NS). Thus, anistreplase is moreeffective than intravenous SK and easier to administer.     

Bacteriocin production by Shigella sonnei isolated from faeces of children with acute diarrhoea

Sousa MÂB, Mendes EN, Apolônio ACM, Farias LM, Magalhães PP. Bacteriocin production by Shigella sonnei isolated from faeces of children with acute diarrhoea. APMIS 2010; 118: 125–35. Shigella is a common agent of diarrhoea, a worldwide major health problem. The bacterium produces bacteriocins; however, the role of these substances as a virulence factor is completely unknown. With the aim to search for colicin production by Shigella sonnei, to evaluate the influence of culture conditions on bacteriocin expression, and to characterize the substance partially, 16 S. sonnei strains isolated from children with diarrhoea were tested for antagonism against members of the intestinal microbiota or agents of diarrhoea. Nine strains exhibited isoantagonism and heteroantagonism against S. flexneri and diarrhoeagenic Escherichia coli. Autoantagonism and antagonism against the intestinal microbiota were not detected. Culture medium and incubation conditions influenced antagonism expression. Antagonism resulting from bacteriophages, low pH, fatty acids, hydrogen peroxide, and chloroform was excluded. The activity of the intracellular fraction obtained with 75% ammonium sulphate was preserved at pH 1.0–11.0, and was found to be reduced by organic solvents and affected by high temperatures and proteases. The antagonistic spectrum and the in vitro conditions for better antagonism expression suggest that the role of colicin in S. sonnei virulence, if any, would be expressed prior to infection, and may regulate population density of enteropathogens by helping in organism transmission.     

Transition to adulthood: validation of the Rotterdam Transition Profile for young adults with cerebral palsy and normal intelligence

The aim of this study was to investigate the validity of the Rotterdam Transition Profile (RTP) to describe the transition process from childhood to adulthood in young adults with cerebral palsy (CP). Participants were recruited from rehabilitation centres and hospital departments of rehabilitation. In total, 81 young adults (47 males, 34 females) with CP and normal intelligence participated (mean age 20y 5mo [SD 1y 4mo] range 18−22y; 95% spastic CP, 48% hemiplegia, 38% diplegia, 14% quadriplegia; 78% Gross Motor Function Classification System Level I, 83% Manual Ability Classification System Level I). The RTP and the Assessment of Life Habits questionnaire are used to measure transition and functioning in daily activities and participation. Almost all participants were in the transition process or had reached an independent adult lifestyle (ranging from 60−100%, housing 42%). Compared with able-bodied peers, young adults with CP lagged behind in their development in housing (25 vs 36%; p <0.05), employment (33 vs 49%; p <0.05), and intimate relationships (37 vs 76%; p <0.01). Associations were found between the phase of transition and age, parents' level of education, gross motor functioning, manual ability, level of education, and level of functioning in daily activities and participation. The RTP is a valid tool to gain more insight into the transition process, at the individual as well as at group level.     

Oral papillary plasmacytosis cleared by radiotherapy

Summary We report a case of oral papillary plasmacytosis which initially responded well to etretinate and, subsequently, was successfully treated with radiotherapy, with minimal side-effects.