Radioimmunoassay for type III procollagen peptide and its application to human liver disease

A sensitive and specific radioimmunoassay was developed for the precursor-specific peptide segment located at the amino end of bovine type III procollagen. Human material showed high cross-reactivity in this assay. Two forms of human procollagen peptides were detected in body fluids. The larger peptide (45K) was found in serum and ascites, and resembled the whole precursor-specific segment which is presumably released from human type III procollagen by a single enzymatic cleavage. The smaller peptide (10K) was found mainly in urine indicating that further degradation of circulating procollagen peptides is required prior to their passage through the kidney. Compared to peptide concentrations in normal human serum two to twenty-fold increases were observed in all patients with alcoholic liver disease, in fifteen of seventeen patients with acute hepatitis, and in ten of fourteen patients with chronic active hepatitis. Much higher levels were detected in ascites fluid. Patients with rheumatoid arthritis and other diseases showed far smaller elevations of the serum peptide. In alcoholic liver disease peptide levels correlated well with inflammation and necrosis observed in liver biopsies, but not with other laboratory parameters.

Biofilm formation by Staphylococcus epidermidis depends on functional RsbU, an activator of the sigB operon: differential activation mechanisms due to ethanol and salt stress

Staphylococcus epidermidis is a common pathogen in medical device-associated infections. Its major pathogenetic factor is the ability to form adherent biofilms. The polysaccharide intercellular adhesin (PIA), which is synthesized by the products of the icaADBC gene cluster, is essential for biofilm accumulation. In the present study, we characterized the gene locus inactivated by Tn917 insertions of two isogenic, icaADBC-independent, biofilm-negative mutants, M15 and M19, of the biofilm-producing bacterium S. epidermidis 1457. The insertion site was the same in both of the mutants and was located in the first gene, rsbU, of an operon highly homologous to the sigB operons of Staphylococcus aureus and Bacillus subtilis. Supplementation of Trypticase soy broth with NaCl (TSB(NaCl)) or ethanol (TSB(EtOH)), both of which are known activators of sigB, led to increased biofilm formation and PIA synthesis by S. epidermidis 1457. Insertion of Tn917 into rsbU, a positive regulator of alternative sigma factor sigma(B), led to a biofilm-negative phenotype and almost undetectable PIA production. Interestingly, in TSB(EtOH), the mutants were enabled to form a biofilm again with phenotypes similar to those of the wild type. In TSB(NaCl), the mutants still displayed a biofilm-negative phenotype. No difference in primary attachment between the mutants and the wild type was observed. Similar phenotypic changes were observed after transfer of the Tn917 insertion of mutant M15 to the independent and biofilm-producing strain S. epidermidis 8400. In 11 clinical S. epidermidis strains, a restriction fragment length polymorphism of the sigB operon was detected which was independent of the presence of the icaADBC locus and a biofilm-positive phenotype. Obviously, different mechanisms are operative in the regulation of PIA expression in stationary phase and under stress induced by salt or ethanol.

Biofilm formation in medical device-related infection

Medical device-associated infections, most frequently caused by coagulase-negative staphylococci, especially Staphylococcus epidermidis, are of increasing importance in modern medicine. Regularly, antimicrobial therapy fails without removal of the implanted device. The most important factor in the pathogenesis of medical device-associated staphylococcal infections is the formation of adherent, multilayered bacterial biofilms. There is urgent need for an increased understanding of the functional factors involved in biofilm formation, the regulation of their expression, and the interaction of those potential virulence factors in device related infection with the host. Significant progress has been made in recent years which may ultimately lead to new rational approaches for better preventive, therapeutic, and diagnostic measures.

Immunochemical characterization of the basement membrane glycoprotein laminin

Laminin was recently characterized as being a major non-collageneous protein of the basement membrane matrix produced by a mouse tumor. It was extracted from the tumor matrix with neutral buffer and purified under non-denaturing conditions. Rabbit and guinea pig antisera raised against laminin or a large pepsin fragment P1 of laminin showed strong binding to both laminin and peptide P1 but only a weak reaction with reduced and alkylated laminin. The major antigenic determinants of laminin were located in a disulfide knot, comprising one third of the molecule, which resisted degradation by pepsin or cyanogen bromide. Minor antigenic determinants shared by the native and reduced protein could also be identified. The data were interpreted as showing that laminin consists of conformationally rigid as well as more flexible domains. Absorption studies with mouse kidney homogenate indicated that authenic basement membranes contain a protein immunologically identical to laminin. Tissues from other species contain a related protein which exhibits partial cross-reaction with mouse laminin. Together with immunofluorescence data the findings demonstrate that laminin, like type IV collagen, occurs in most basement membranes of the body.

Identification of three essential regulatory gene loci governing expression of Staphylococcus epidermidis polysaccharide intercellular adhesin and biofilm formation

The formation of adherent multilayered biofilms embedded into a glycocalyx represents an essential factor in the pathogenesis of Staphylococcus epidermidis biomaterial-related infections. Using biofilm-producing S. epidermidis 1457 and transposon Tn917 carried on plasmid pTV1ts, we isolated nine isogenic biofilm-negative transposon mutants. Transduction by S. epidermidis phage 71 was used to prove the genetic linkage of transposon insertions and altered phenotypes. Mapping of the different transposon insertions by Southern hybridization and pulsed-field gel electrophoresis indicated that these were inserted in four unlinked genetic loci. According to their phenotypes, including quantitative differences in biofilm production in different growth media, in the amount of the polysaccharide intercellular adhesin (PIA) produced, in the hemagglutination titers, and in the altered colony morphology, the mutants could be separated into four phenotypic classes corresponding with the genetic classes. Synthesis of PIA was not detectable with class I and II mutants, whereas the amount of PIA produced reflected the residual degree of biofilm production of class III and IV mutants in different growth media. Chromosomal DNA flanking the transposon insertions of five class I mutants was cloned and sequenced, and the insertions were mapped to different locations of icaADBC, representing the synthetic genes for PIA. Expression of icaADBC from a xylose-dependent promoter in the different isogenic mutant classes reconstituted biofilm production in all mutants. In a Northern blot analysis no icaADBC-specific transcripts were observed in RNA isolated from mutants of classes II, III, and IV. Apparently, in addition to icaADBC, three other gene loci have a direct or indirect regulatory influence on expression of the synthetic genes for PIA on the level of transcription.

Essential functional role of the polysaccharide intercellular adhesin of Staphylococcus epidermidis in hemagglutination

Hemagglutination of erythrocytes is a common property of Staphylococcus epidermidis strains, which is related to adherence and biofilm formation and may be essential for the pathogenesis of biomaterial-associated infections caused by S. epidermidis. In three independent biofilm-producing, hemagglutination-positive S. epidermidis isolates, interruption of the icaADBC operon essential for polysaccharide intercellular adhesin (PIA) synthesis by Tn917 insertions led to a hemagglutination-negative phenotype. An immunoglobulin G fraction of antiserum to PIA greatly reduced hemagglutination. Purified PIA led to a 64-fold decrease of hemagglutination titers of these strains; however, it did not mediate hemagglutination by itself. These observations define PIA as the hemagglutinin of S. epidermidis or at least as its major functional component.

The Yersinia enterocolitica pYV virulence plasmid contains multiple intrinsic DNA bends which melt at 37 degrees C

Temperature has a pleiotropic effect on Yersinia enterocolitica gene expression. Temperature-dependent phenotypes include the switching between two type III protein secretion systems, flagellum biosynthesis (</=30 degrees C) and virulence plasmid-encoded Yop secretion (37 degrees C). The mechanism by which temperature exerts this change in genetic programming is unclear; however, altered gene expression by temperature-dependent changes in DNA topology has been implicated. Here, we present evidence that the Y. enterocolitica virulence plasmid, pYV, undergoes a conformational transition between 30 and 37 degrees C. Using a simplified two-dimensional, single-gel assay, we show that pYV contains multiple regions of intrinsic curvature, including virF, the positive activator of virulence genes. These bends are detectable at 30 degrees C but melt at 37 degrees C, the temperature at which the cells undergo phenotypic switching. We also show that pACYC184, a plasmid used as a reporter of temperature-induced changes in DNA supercoiling, has a single region of intrinsic bending detected by our assay. Topoisomers of pACYC184, with and without this bend, isolated from Y. enterocolitica were resolved by using chloroquine gels. The single bend has a dramatic influence on temperature-dependent DNA supercoiling. These data suggest that the Y. enterocolitica pYV plasmid may undergo a conformational change at the host temperature due to melting of DNA bends followed by compensatory adjustments in superhelical density. Hence, changes in DNA topology may be the temperature-sensing mechanism for virulence gene expression in Y. enterocolitica and other enteric pathogens.

Basal lamina glycoproteins are produced by neuroblastoma cells

Murine neuroblastoma cells have been widely used as a model system for neuronal cells as they can be induced to differentiate in culture by various stimuli, such as dibutyryl cyclic AMP (dbcAMP), prostaglandin, and serum starvation. The cells respond with assembly of microtubules, leading to neurite outgrowth, with increased activity of neuronal-specific enzymes, tyrosine hydroxylase, choline acetyltransferase and acetylcholine-esterase, and synthesis of neurotransmitters. The differentiated cells lose tumorigenicity. Cell-to-substratum adhesion is evidently crucial for neurone extension in vitro. Neurite outgrowth is induced by treatments that increase cell-to-substratum adhesion in some neuronal cell cultures. We have now identified the major high molecular weight proteins synthesized and secreted by murine C1300 neuroblastoma cells as fibronectin, laminin and type IV procollagen, of which the latter two were also found to be deposited in pericellular matrix form.

Serum and urine analysis of the aminoterminal procollagen peptide type III by radioimmunoassay with antibody Fab fragments

A radioimmunoassay based on antibody Fab fragments was developed for the aminoterminal peptide Col 1-3 of bovine type III procollagen. This assay does not distinguish the intact aminopropeptide Col 1-3 from its globular fragment Col 1. Parallel inhibition profiles were observed with human serum and urine allowing the simultaneous quantitative determination of intact and fragmented antigens in these samples. Most of the material has a size similar to that of fragment Col 1 indicating that the aminopropeptide is degraded under physiologic conditions. The concentration of aminopeptide in normal sera was in the range 15-63 ng/ml. Daily excretion was found to be in the range 30-110 micrograms. More than 50% of patients with alcoholic hepatitis and liver cirrhosis showed elevated serum levels of aminopropeptide by the Fab assay. Elevated concentrations were detected more frequently with an antibody radioimmunoassay which measures mainly the intact form of the aminopropeptide. It is suggested that analysis of patients material by both assays could improve their diagnostic application.

Characterization of pepsin fragments of laminin in a tumor basement membrane. Evidence for the existence of related proteins

Laminin was extracted with neutral buffer from a tumor basement membrane and subjected to extensive degradation by pepsin. The treatment released two homogenous fragments P1 (Mr = 290,000) and P2 (Mr = 45,000) in addition to a mixture of smaller peptides. Fragments P1 and P2 together contained more than 90% of the disulfide bonds and accounted for about one third of the mass of laminin. Both peptides differed in amino acid composition, immunological properties and a complex chain structure demonstrating the existence of two disulfide-bonded domains in the molecule. Part of the laminin in the tumor matrix could only be solubilized by pepsin treatment and several fragments were purified. The major fragment P1i closely resembled P1 of soluble laminin in its chemical and immunological properties. Minor fragments Pa, Pb, Pc and Pd (Mr = 44,000-74,000) were only related to P1 or P2 in amino acid composition, chain pattern and antigenicity. The data were interpreted as indicating that proteins similar but not identical to laminin exist in the basement membrane and account for the minor peptide variants.

Has there been any improvement in the staging of gastric cancer? Findings from the German Gastric Cancer TNM Study Group

This multicenter observational study examined the survival of 1420 patients with histologically proven carcinoma of the stomach. From April 1982 through October 1984, 1360 (95%) patients underwent surgery, 988 (72%) had resections, and 372 (28%) minor surgical procedures. The percentage of patients who have been followed until death or 3 to 5 years was 99.4%. Patients were staged preoperatively and intraoperatively and by pathologists using the old (1978) and new (1987) TNM stage groupings and 5-year survival was analyzed. Subgroups of patients who changed their stage group according to the new stage definitions were analyzed separately. Only age was an important prognostic factor for survival in Stage IA (P less than 0.05) and Stage IB (P less than 0.01). Residual tumor after surgery was most important for survival in Stage II (P less than 0.01) and Stage IIIA (P less than 0.001). This indicates that improvements of stage definitions for individual prognosis can only be achieved by adding data concerning the presence or absence of residual tumor (R classification).

Radioimmunoassay for the aminoterminal peptide of procollagen p alpha 1(I)-chain

Peptides derived from the aminoterminal portion of the palpha1(I)-chain of calf and sheep procollagen were labeled with iodine-125. Despite changes in electrophoretic homogeneity after labeling, reaction of the labeled peptide with antisera to unlabeled peptide was retained. Antisera to procollagen or the isolated procollagen peptide showed high titers for the native peptide, a much weaker binding with the reduced and alkylated peptide and little or no reaction with collagen. Antisera to collagen showed strong binding with collagen and a weaker but distinct reaction with the procollagen peptide. Evidence was obtained that a minor contaminant of procollagen peptide was present in the acid-extracted collagen and that there were no shared antigenic determinants. Bovine serum and amniotic fluid contained 1-10 mug/ml reactive antigen. These results indicate that the labeled peptides can be used as a specific, sensitive and accurate assay for the amino-terminal portion of procollagen in biological samples.

Anticipating explanations in relative clause processing

We show that comprehenders' expectations about upcoming discourse coherence relations influence the resolution of local structural ambiguity. We employ cases in which two clauses share both a syntactic relationship and a discourse relationship, and hence in which syntactic and discourse processing might be expected to interact. An off-line sentence-completion study and an on-line self-paced reading study examined readers' expectations for high/low relative-clause attachments following implicit-causality and non-implicit causality verbs (John detests/babysits the children of the musician who…). In the off-line study, the widely reported low-attachment preference for English is observed in the non-implicit causality condition, but this preference gives way to more high attachments in the implicit-causality condition in cases in which (i) the verb's causally implicated referent occupies the high-attachment position and (ii) the relative clause provides an explanation for the event described by the matrix clause (e.g., …who are arrogant and rude). In the on-line study, a similar preference for high attachment emerges in the implicit-causality context-crucially, before the occurrence of any linguistic evidence that the RC does in fact provide an explanation-whereas the low-attachment preference is consistent elsewhere. These findings constitute the first demonstration that expectations about ensuing discourse coherence relationships can elicit full reversals in syntactic attachment preferences, and that these discourse-level expectations can affect on-line disambiguation as rapidly as lexical and morphosyntactic cues.

Histamine and peptic ulcer: a prospective study of mucosal histamine concentration in duodenal ulcer patients and in control subjects suffering from various gastrointestinal diseases

In a prospective study the histamine content of the mucosa of the body of the stomach was measured in 100 patients consisting of control subjects, patients with duodenal ulcer and patients suffering from various gastrointestinal diseases. The histamine content was found to be 43 mug/g in male control subjects (median) while in duodenal ulcer patients levels attained were significantly lower by about 30 per cent. In all the other groups of patients histamine concentrations in gastric mucosa were found to be "normal". Since in most species it is extremely diffcult to alter the mucosal histamine concentration by any form of treatment, the diminished histamine content of the gastric mucosa in patients with duodenal ulcer seems remarkable. Among several possible explanations offered for this finding we think the most likely is that histamine release is increased in duodenal ulcer disease.

Dose-related healing of duodenal ulcer with the proton pump inhibitor lansoprazole

Lansoprazole (AG 1749) is a novel substituted benzimidazole which inhibits gastric acid secretion by blocking H+,K(+)-ATPase. This randomized, double-blind multicentre trial studied the dose-response relationship of lansoprazole on ulcer healing and compared it with ranitidine in 314 out-patients with endoscopically assessed, symptomatic duodenal ulcer. Cumulative healing rates with Lansoprazole 7.5, 15, and 30 mg o.m. were 48, 59, and 74% at 2 weeks and 75, 84, and 95% at 4 weeks, respectively (intention-to-treat); the difference of the healing rates between 7.5 and 30 mg groups was significant (P less than 0.001). Corresponding healing rates for 300 mg ranitidine nocte were 51 and 89%. Pain relief was similar in all treatment groups. Lansoprazole was well tolerated. During a follow-up of 6 months relapse rates after lansoprazole 7.5, 15, and 30 mg were 21, 29, and 22%, respectively; the relapse rate after ranitidine 300 mg was 20%. In conclusion, lansoprazole provides faster healing of duodenal ulcer than ranitidine and a similar relapse pattern. For further trials in peptic ulcer disease a daily dose of lansoprazole 30 mg o.m. is recommended.

Correlation of biofilm expression types of Staphylococcus epidermidis with polysaccharide intercellular adhesin synthesis: evidence for involvement of icaADBC genotype-independent factors

IcaADBC-encoded proteins mediate synthesis of the intercellular polysaccharide adhesin (PIA), which is essentially involved in Staphylococcus epidermidis biofilm formation. Seventy S. epidermidis isolates were investigated for their ability to form biofilm and synthesize PIA in different growth media including trypticase soy broth obtained from Becton Dickinson (TSBBBL), or Oxoid (TSB(OXOID)), and TSB(OXOID) supplemented with 0.5% N-acetylglucosamine, and for the presence of icaADBC. Dependent on the medium used (TSB(BBL) or TSB(OXOID)), the isolates exhibited a differential expression of PIA and biofilm formation, with 51 (72.85%) and 34 (48.57%) being biofilm positive, respectively. Using these growth media four different expression phenotypes were differentiated: similar quantities of biofilm formation in both TSBBBL and TSB(OXOID) (11 isolates, type A), significantly reduced biofilm expression in TSB(OXOID) compared to TSB(BBL) (23 isolates, type B), biofilm negative in TSB(OXOID) but biofilm producing in TSB(BBL) (17 isolates, type C) and biofilm negative in both media (19 isolates, type D). For all strains a biofilm-positive phenotype in a specific medium was closely linked to expression of PIA in that medium. All but one strain of expression type A-C and 7/19 expression type D strains were icaADBC positive. On the basis of restriction fragment length polymorphisms, the isolates were classified into two main icaADBC genotypes. There was no association between the observed biofilm-expression types and a defined icaADBC genotype. In the biofilm-negative S. epidermidis 5179, isolated from a ventriculo-atrial shunt infection, the insertion of IS257 interrupted the transcription of icaADBC, resulting in a PIA- and biofilm-negative phenotype. In all other icaADBC-positive, biofilm-negative isolates no major alterations of the icaADBC gene locus were identified. Obviously, expression of icaADBC, PIA synthesis and biofilm formation are integrated into a complex regulatory network involving other determinants independent of icaADBC genotype. Inactivation of icaADBC by IS elements is apparently a rare cause of a biofilm-negative phenotype in clinical S. epidermidis isolates.

Proximal compared with distal adenocarcinoma of the stomach: differences and consequences. German Gastric Cancer TNM Study Group

Interest in leading prognostic determinants of proximal gastric adenocarcinoma (PGA) in comparison with distally located adenocarcinoma (DLA) of the stomach led to an analysis of data from 506 patients with PGA and 484 patients with DLA operated on between 1 April 1982 and 31 October 1984 and participating in a multicentre observational study to validate tumour node metastasis (TNM) stage groupings. The proportion of men with PGA was slightly higher than that of men with DLA (69 versus 63 per cent). Men more often had cardia carcinomas than women (14 versus 9 per cent); 74 per cent of these men but only 43 per cent of the women were less than 65 years old. Evaluation of data by a log-linear model indicated a strong partial association (P less than 0.001) between age and site; patients younger than 65 years more often had PGA than older patients. Advanced tumour stage and the intestinal type of carcinoma were more frequently seen in the elderly. More than twice as many patients with PGA in comparison with those with DLA (35 versus 15 per cent) had palliative surgery (moderate association, P less than 0.05). This may have resulted from different stages at different sites; advanced carcinomas (TNM stages IIIb and IV) were more often diagnosed in patients with PGA than in those with DLA (60 versus 38 per cent). Residual tumour left after surgery was associated with deeper infiltration (P less than 0.001). No difference between PGA and DLA groups with respect to histological type of carcinoma was established, but residual tumour was more frequently associated with a diffuse type carcinoma (P less than 0.01). An overall tendency to poorer long-term prognosis in PGA was seen for all TNM stages, with and without residual tumour, except for TNM stage II with residual tumour, even though patients with PGA were younger than those with DLA. These differences in long-term prognosis, however, are based primarily on poorer short-term survival for PGA, particularly for TNM stages Ib and II without residual tumour. A significant risk of surgical management, particularly for early-stage tumours situated in the upper part of the stomach, has therefore been recognized. Surgeons should appreciate the higher surgical mortality rate for patients with PGA when curative treatment requires more risky surgical techniques.

Low rate of procollagen conversion in dermatosparactic sheep fibroblasts is paralleled by increased synthesis of type I and type III collagens

Dermatosparaxis is a genetic defect found in humans and animals, which affects the conversion of procollagen to collagen and aminopropeptides . Under cell culture conditions a reduction of the release of aminopropeptides is paralleled by an increased synthesis of collagens type I and III. This fact provides further evidence for a regulatory involvement of aminopropeptides in the biosynthesis of collagen.