Demonstration of factor H-like protein 1 binding to Treponema denticola, a pathogen associated with periodontal disease in humans

Treponema denticola is an important contributor to periodontal disease. In this study we investigated the ability of T. denticola to bind the complement regulatory proteins factor H and factor H-like protein 1 (FHL-1). The binding of these proteins has been demonstrated to facilitate evasion of the alternative complement cascade and/or to play a role in adherence and invasion. Here we demonstrate that T. denticola specifically binds FHL-1 via a 14-kDa, surface-exposed protein that we designated FhbB. Consistent with its FHL-1 binding specificity, FhbB binds only to factor H recombinant fragments spanning short consensus repeats (SCRs) 1 to 7 (H7 construct) and not to SCR constructs spanning SCRs 8 to 15 and 16 to 20. Binding of H7 to FhbB was inhibited by heparin. The specific involvement of SCR 7 in the interaction was demonstrated using an H7 mutant (H7AB) in which specific charged residues in SCR 7 were replaced by alanine. This construct lost FhbB binding ability. Analyses of the ability of FHL-1 bound to the surface of T. denticola to serve as a cofactor for factor I-mediated cleavage of C3b revealed that C3b is cleaved in an FHL-1/factor I-independent manner, perhaps by an unidentified protease. Based on the data presented here, we hypothesize that the primary function of FHL-1 binding by T. denticola might be to facilitate adherence to FHL-1 present on anchorage-dependent cells and in the extracellular matrix.     

Loss of cell polarity causes severe brain dysplasia in Lgl1 knockout mice

Disruption of cell polarity is seen in many cancers; however, it is generally considered a late event in tumor progression. Lethal giant larvae (Lgl) has been implicated in maintenance of cell polarity in Drosophila and cultured mammalian cells. We now show that loss of Lgl1 in mice results in formation of neuroepithelial rosette-like structures, similar to the neuroblastic rosettes in human primitive neuroectodermal tumors. The newborn Lgl1(-/-) pups develop severe hydrocephalus and die neonatally. A large proportion of Lgl1(-/-) neural progenitor cells fail to exit the cell cycle and differentiate, and, instead, continue to proliferate and die by apoptosis. Dividing Lgl1(-/-) cells are unable to asymmetrically localize the Notch inhibitor Numb, and the resulting failure of asymmetric cell divisions may be responsible for the hyperproliferation and the lack of differentiation. These results reveal a critical role for mammalian Lgl1 in regulating of proliferation, differentiation, and tissue organization and demonstrate a potential causative role of disruption of cell polarity in neoplastic transformation of neuroepithelial cells.     

Functional homology of virulence plasmids in Salmonella gallinarum, S. pullorum, and S. typhimurium.

The virulence-associated plasmids of strains of Salmonella gallinarum and S. pullorum were transferred separately by mobilization with the F plasmid into virulence plasmid-cured derivatives of S. gallinarum, S. pullorum, and S. typhimurium and into a prototrophic Escherichia coli K-12 strain. The transconjugants were tested for virulence in chickens of different ages and in mice. The S. gallinarum and S. pullorum plasmids were able to restore full virulence in the three Salmonella strains, thus demonstrating functional homology in virulence plasmids from these Salmonella serotypes and biotypes. The virulence phenotypes of the transconjugants remained the same as that of the parent strain of the recipient. This, together with the fact that E. coli K-12 containing either of the virulence plasmids was avirulent for chickens, suggested that in addition to plasmid genes, chromosomal genes are important in determining virulence, particularly in determining the ability to survive and multiply in the cells of the reticuloendothelial system. The virulence plasmids were not self-transmissible and could not be transduced by temperate bacteriophages lysogenizing field strains of S. gallinarum. They were not in the same incompatibility group as F but were fi+.     

Rapid protection of gnotobiotic pigs against experimental salmonellosis following induction of polymorphonuclear leukocytes by avirulent Salmonella enterica

Oral inoculation of 5-day-old gnotobiotic pigs with Salmonella enterica serovar Typhimurium strain F98 resulted in severe enteritis and invasive disease. Preinoculation 24 h earlier with an avirulent mutant of Salmonella enterica serovar Infantis (1326/28) completely prevented disease for up to 14 days (when the experiment was terminated). S. enterica serovar Infantis colonized the alimentary tract well, with high bacterial counts in the intestinal lumen but with almost no invasion into the tissues. Unprotected pigs had high S. enterica serovar Typhimurium counts in the intestines, blood, and major nonintestinal organs. Recovery of this strain from the blood and major organs in S. enterica serovar Infantis-protected pigs was substantially reduced despite the fact that intestinal counts were also very high. Protection against disease thus did not involve a colonization exclusion phenomenon. Significant (P < 0.05) infiltration of monocytes/macrophages was observed in the submucosal regions of the intestines of both S. enterica serovar Infantis-protected S. enterica serovar Typhimurium-challenged pigs and unprotected S. enterica serovar Typhimurium-challenged pigs. However, only polymorphonuclear neutrophils (PMNs) were observed throughout the villus, where significant (P < 0.05) numbers infiltrated the lamina propria and the subnuclear and supranuclear regions of the epithelia, indicating that PMN induction and positioning following S. enterica serovar Infantis inoculation was consistent with rapid protection against the challenge strain. Similarly, in vitro experiments using a human fetal intestinal epithelial cell line (INT 407) demonstrated that, although significantly (P < 0.05) fewer S. enterica serovar Infantis than S. enterica serovar Typhimurium organisms invaded the monolayers, S. enterica serovar Infantis induced an NF-kappaB response and significantly (P < 0.05) raised interleukin 8 levels and transmigration of porcine PMN. The results of this study suggest that attenuated Salmonella strains can protect the immature intestine against clinical salmonellosis by PMN induction. They also demonstrate that PMN induction is not necessarily associated with clinical symptoms and/or intestinal pathology.     

Population structure and admixture in Cerro Largo, Uruguay, based on blood markers and mitochondrial DNA polymorphisms.

Recent studies of the Uruguayan population revealed different amounts of Amerindian and African genetic contributions. Our previous analysis of Afro-Uruguayans from the capital city of the Department of Cerro Largo showed a high proportion of African genes, and the effects of directional mating involving Amerindian women. In this paper, we extended the analysis to a sample of more than 100 individuals representing a random sample of the population of the whole Department. Based on 18 autosomal markers and one X-linked marker, we estimated 82% European, 8% Amerindian, and 10% African contributions to their ancestry, while from seven mitochondrial DNA site-specific polymorphic markers and sequences of hypervariable segment I, we determined 49% European, 30% Amerindian, and 21% African maternal contributions. Directional matings between Amerindian women and European men were detected, but differences involving Africans were not significant. Data about the specific origins of maternal lineages were also provided, and placed in a historical context.     

A randomised controlled trial to test the feasibility of a collaborative care model for the management of depression in older people

BACKGROUND: Depression is the most common mental health disorder in people aged over 65 years. Late-life depression is associated with chronic illness and disability. AIM: To investigate the feasibility of a collaborative care model for depression in older people in a primary care setting. DESIGN OF STUDY: Randomised controlled trial with 16-weeks follow up. SETTING: A primary care trust in Manchester. METHOD: Participants were 105 people aged 60 years or older who scored 5 or more on the Geriatric Depression Scale; 53 were randomly allocated to an intervention group and 52 to a usual care group. The intervention group received care managed by a community psychiatric nurse who delivered an intervention comprising a facilitated self-help programme with close liaison with primary care professionals and old-age psychiatry according to a defined protocol. The usual care group received usual GP care. A nested qualitative study explored the views of the health professionals and patients regarding the acceptability and effectiveness of the intervention. RESULTS: The main outcome measure was recovery from depression. Patients in the intervention group were less likely to suffer from major depressive disorder at follow up compared with usual care (0.32, 95% confidence = interval = 0.11 to 0.93, P = 0.036). The qualitative component of the study demonstrated the acceptability of the intervention to patients. CONCLUSION: A model of collaborative care for older people with depression, used in a primary care setting with a facilitated self-help intervention is more effective than usual GP care. This study demonstrates that the implementation of a collaborative care model is feasible in UK primary care and that the intervention is effective and acceptable to patients.     

Duplication 18q syndrome

Some variation in the phenotype of patients with dup(18q) is recognized. Our patient has the phenotype described for dup(18qter).     

Synthesis and characterisation of poly(arylene sulfides), 6. Synthesis of block copoly(arylene sulfides)

Novel ABA block copolymers of poly(1,4-phenylene sulfide) (PPS(A)) and poly-(2-methyl-1,4-phenylene sulfide) (PMPS(B)) were synthesised from bis(4-bromophenyl) sulfone (BBS) by sequential reaction with copper(I) 4-bromo-2-methylbenzenethiolate (CBMT) and copper(I) 4-bromobenzenethiolate (CBT). PPS, PMPS and PPS/PMPS random copolymers were also prepared to aid block copolymer characterisation. Polymer fractions were studied by hot-stage microscopy to evaluate melting ranges, and molar masses were computed from bromine end-group concentrations and from gel permeation chromatography studies. Compositional analyses were made by IR and ¹H NMR spectroscopy leading to confirmation of the block copolymer structure and to evaluation of the degrees of polymerisation of the individual blocks.     

High expression of MDR1, MRP1, and MRP3 in the hepatic progenitor cell compartment and hepatocytes in severe human liver disease

An increase in bile ductular structures is observed in diverse human liver diseases. These structures harbour the progenitor cell compartment of the liver. Since ATP-binding cassette (ABC) transporters may have a cytoprotective role in liver disease, an immunohistochemical study was performed on human liver specimens from patients with primary biliary cirrhosis (PBC), chronic hepatitis C virus (HCV) infection, submassive cell necrosis, and normal liver. The expression of MDR1, MDR3, BSEP, MRP1, MRP2, and MRP3 was determined using specific antibodies. Dilution series were constructed to determine the critical staining level in order to estimate the factor of up-regulation. In normal liver, hepatocytes showed canalicular staining for MDR3, BSEP, and MRP2. MDR1 stained the canalicular membrane of hepatocytes as well as that of cholangiocytes. MRP3 showed low immunoreactivity of bile duct epithelial cells and centrilobular hepatocytes only. Normal liver showed no immunoreactivity for MRP1. In diseased liver, the expression of MDR3, BSEP, and MRP2 was relatively stable. In PBC, HCV, and submassive necrosis, the expression levels of MDR1, MRP1, and MRP3 were increased. The strongest immunoreactivity was seen after submassive necrosis, where remaining islands of hepatocytes showed strong canalicular staining for MDR1 and MRP3. Regenerating bile ductules at the interface of portal tracts and necrotic areas stained intensely for MDR1, MRP1, and MRP3. In conclusion, MDR1, MRP1, and MRP3 are up-regulated in hepatocytes in severe human liver disease. Strong MDR1, MRP1, and MRP3 reactivity is seen in regenerating human bile ductules.