The fat-derived hormone adiponectin reverses insulin resistance associated with both lipoatrophy and obesity

Adiponectin is an adipocyte-derived hormone. Recent genome-wide scans have mapped a susceptibility locus for type 2 diabetes and metabolic syndrome to chromosome 3q27, where the gene encoding adiponectin is located. Here we show that decreased expression of adiponectin correlates with insulin resistance in mouse models of altered insulin sensitivity. Adiponectin decreases insulin resistance by decreasing triglyceride content in muscle and liver in obese mice. This effect results from increased expression of molecules involved in both fatty-acid combustion and energy dissipation in muscle. Moreover, insulin resistance in lipoatrophic mice was completely reversed by the combination of physiological doses of adiponectin and leptin, but only partially by either adiponectin or leptin alone. We conclude that decreased adiponectin is implicated in the development of insulin resistance in mouse models of both obesity and lipoatrophy. These data also indicate that the replenishment of adiponectin might provide a novel treatment modality for insulin resistance and type 2 diabetes.

The systems biology markup language (SBML): a medium for representation and exchange of biochemical network models

MOTIVATION

Molecular biotechnology now makes it possible to build elaborate systems models, but the systems biology community needs information standards if models are to be shared, evaluated and developed cooperatively.

RESULTS

We summarize the Systems Biology Markup Language (SBML) Level 1, a free, open, XML-based format for representing biochemical reaction networks. SBML is a software-independent language for describing models common to research in many areas of computational biology, including cell signaling pathways, metabolic pathways, gene regulation, and others.

AVAILABILITY

The specification of SBML Level 1 is freely available from http://www.sbml.org/

Analysis of the mouse transcriptome based on functional annotation of 60,770 full-length cDNAs

Only a small proportion of the mouse genome is transcribed into mature messenger RNA transcripts. There is an international collaborative effort to identify all full-length mRNA transcripts from the mouse, and to ensure that each is represented in a physical collection of clones. Here we report the manual annotation of 60,770 full-length mouse complementary DNA sequences. These are clustered into 33,409 'transcriptional units', contributing 90.1% of a newly established mouse transcriptome database. Of these transcriptional units, 4,258 are new protein-coding and 11,665 are new non-coding messages, indicating that non-coding RNA is a major component of the transcriptome. 41% of all transcriptional units showed evidence of alternative splicing. In protein-coding transcripts, 79% of splice variations altered the protein product. Whole-transcriptome analyses resulted in the identification of 2,431 sense-antisense pairs. The present work, completely supported by physical clones, provides the most comprehensive survey of a mammalian transcriptome so far, and is a valuable resource for functional genomics.

Isolation and characterization of GBP28, a novel gelatin-binding protein purified from human plasma

By use of its affinity to gelatin-Cellulofine, a novel protein, GBP28 (gelatin-binding protein of 28 kDa), was obtained from human plasma. GBP28 bound to gelatin-Cellulofine could be eluted with 1 M NaCl. By analysis of its amino-terminal amino acid sequences and the peptides obtained by protease digestion, GBP28 was identified as a novel protein. After repeated gel chromatography of the 1 M NaCl eluate from gelatin-Cellulofine, about 50 micrograms of GBP28 was purified from 500 ml of human plasma. On gel chromatography, the protein migrated as a molecule of about 420 kDa. On SDS-PAGE, its molecular mass was 28 kDa under reducing conditions and 68 kDa under nonreducing conditions. Recently, human mRNA specific to adipose tissue, cDNA clone apM1, has been registered [Maeda, K., Okubo, K., Shimomura, I., Funahashi, T., Matsuzawa, Y., and Matsubara, K. (1996) Biochem. Biophys. Res. Commun. 221, 286-289]. The assumed amino acid sequence of cDNA clone apM1 contained all the sequences of GBP28 and its peptides. Therefore, it is evident that the cDNA clone apM1 encodes GBP28 and the protein is specific to adipose tissue. The clone encodes a polypeptide of 244 amino acids with a secretory signal sequence at the amino terminus, a small non-helical region, a stretch of 22 collagen repeats and a globular domain. Thus, GBP28 appears to belong to a family of proteins possessing a collagen-like domain through which they form homo-trimers, which further combine to make oligomeric complexes. Although its biological function is presently unclear, its adipocyte-specific expression suggests that GBP28 may function as an endogenous factor involved in lipid catabolism and storage or whole body metabolism.

Identification of the bactericidal domain of lactoferrin

We report the existence of a previously unknown antimicrobial domain near the N-terminus of lactoferrin in a region distinct from its iron-binding sites. A single active peptide representing this domain was isolated following gastric pepsin cleavage of human lactoferrin, and bovine lactoferrin, and sequenced by automated Edman degradation. The antimicrobial sequence was found to consist mainly of a loop of 18 amino acid residues formed by a disulfide bond between cysteine residues 20 and 37 of human lactoferrin, or 19 and 36 of bovine lactoferrin. Synthetic analogs of this region similarly exhibited potent antibacterial properties. The active peptide of bovine lactoferrin was more potent than that of human lactoferrin having effectiveness against various Gram-negative and Gram-positive bacteria at concentrations between 0.3 microM and 3.0 microM, depending on the target strain. The effect of the isolated domain was lethal causing a rapid loss of colony-forming capability. Our studies suggest this domain is the structural region responsible for the bacterial properties of lactoferrin.

Functional annotation of a full-length mouse cDNA collection

The RIKEN Mouse Gene Encyclopaedia Project, a systematic approach to determining the full coding potential of the mouse genome, involves collection and sequencing of full-length complementary DNAs and physical mapping of the corresponding genes to the mouse genome. We organized an international functional annotation meeting (FANTOM) to annotate the first 21,076 cDNAs to be analysed in this project. Here we describe the first RIKEN clone collection, which is one of the largest described for any organism. Analysis of these cDNAs extends known gene families and identifies new ones.

Amino-acid sequence and oligosaccharide attachment sites of human erythrocyte glycophorin

Glycophorin, the major sialoglycoprotein of the human erythrocyte membrane, is composed of 131 amino acids and an average of 16 oligosaccharide chains. Fifteen oligosaccharides are linked to threonine/serine residues via O-glycosidic bonds, and one more complex unit is attached to asparagine. The location of each of these oligosaccharides and the complete amino-acid sequence of this molecular have been determined by Edman degradation techniques. Glycophorin appears to be organized into three distinct "domains" on the basis of the locations of glycosylated amino acids and the clustering of residues of similar type. These include (i) a glycosylated segment composed of approximately 64 residues from the NH2-terminus, (ii) a "hydrophobic" segment of approximately 32 nonpolar residues, and (iii) a COOH-terminal segment, composed of approximately 35 residues, which has an unusual concentration of hydrophilic amino acids. This unique structure is consistent with the earlier suggestions that glycophorin is one of the major "intrinsic" membrane proteins which has a transmembrane orientation.

Antibacterial spectrum of lactoferricin B, a potent bactericidal peptide derived from the N-terminal region of bovine lactoferrin

A physiologically diverse range of Gram-positive and Gram-negative bacteria was found to be susceptible to inhibition and inactivation by lactoferricin B, a peptide produced by gastric pepsin digestion of bovine lactoferrin. The list of susceptible organisms includes Escherichia coli, Salmonella enteritidis, Klebsiella pneumoniae, Proteus vulgaris, Yersinia enterocolitica, Pseudomonas aeruginosa, Campylobacter jejuni, Staphylococcus aureus, Streptococcus mutans, Corynebacterium diphtheriae, Listeria monocytogenes and Clostridium perfringens. Concentrations of lactoferricin B required to cause complete inhibition of growth varied within the range of 0.3 to 150 micrograms/ml, depending on the strain and the culture medium used. The peptide showed activity against E. coli O111 over the range of pH 5.5 to 7.5 and was most effective under slightly alkaline conditions. Its antibacterial effectiveness was reduced in the presence of Na+, K+, Mg2+ or Ca2+ ions, or in the presence of various buffer salts. Lactoferricin B was lethal, causing a rapid loss of colony-forming capability in most of the species tested. Pseudomonas fluorescens, Enterococcus faecalis and Bifidobacterium bifidum strains were highly resistant to this peptide.

Primary structure of human erythrocyte glycophorin A. Isolation and characterization of peptides and complete amino acid sequence

Peptides of glycophorin AMN were prepared by cyanogen bromide cleavage and by chymotryptic and tryptic digestion. Cyanogen bromide cleavage produces three fragments which account for the entire polypeptide chain. Trypsin and chymotrypsin cleave completely at several sites, but incompletely at sites within the glycosylated segment of the polypeptide chain. Some of the latter sites become accessible to proteolysis after desialation in addition to exposure of new sites for cleavage. The amino acid sequence of glycophorin AMN has been determined by manual Edman degradation, using both the direct Edman and the dansyl-Edman procedures simultaneously for determination of glycosylated amino acid residues. The automated procedure was used for sequence determination of a hydrophobic peptide. Glycophorin A is a polypeptide chain of 131 amino acid residues and contains 16 oligosaccharide units attached to the amino-terminal third of the molecule. Fifteen oligosaccharides are linked O-glycosidically to either threonine or serine residues and one complex oligosaccharide unit is attached N-glycosidically to an asparagine residue. Amino-terminal sequences are different for glycophorin AM and AN, the two forms of the glycophorin A molecule coded for by genes at the MN locus. The differences in sensitivity to proteases of various sites on glycophorin A seem to be due to heterogeneity in the carbohydrate components and not to differences in the primary structure of the polypeptide chains. This work contains a number of revisions and corrections of earlier preliminary reports [Segrest, J.P., Jackson, R. chem. Biophys. Res. Commun, 49, 964-969; Tomita, M., & Marchesi, V.T. (1975) Proc. Natl. Acad. Sci. U.S.A. 72, 2964-2968].

Disruption of the fibroblast growth factor-2 gene results in decreased bone mass and bone formation

Basic fibroblast growth factor (FGF-2), an important modulator of cartilage and bone growth and differentiation, is expressed and regulated in osteoblastic cells. To investigate the role of FGF-2 in bone, we examined mice with a disruption of the Fgf2 gene. Measurement of trabecular bone architecture of the femoral metaphysis of Fgf2(+/+) and Fgf2(-/-) adult mice by micro-CT revealed that the platelike trabecular structures were markedly reduced and many of the connecting rods of trabecular bone were lost in the Fgf2(-/-) mice. Dynamic histomorphometry confirmed a significant decrease in trabecular bone volume, mineral apposition, and bone formation rates. In addition, there was a profound decreased mineralization of bone marrow stromal cultures from Fgf2(-/-) mice. This study provides strong evidence that FGF-2 helps determine bone mass as well as bone formation.

E-CELL: software environment for whole-cell simulation

MOTIVATION

Genome sequencing projects and further systematic functional analyses of complete gene sets are producing an unprecedented mass of molecular information for a wide range of model organisms. This provides us with a detailed account of the cell with which we may begin to build models for simulating intracellular molecular processes to predict the dynamic behavior of living cells. Previous work in biochemical and genetic simulation has isolated well-characterized pathways for detailed analysis, but methods for building integrative models of the cell that incorporate gene regulation, metabolism and signaling have not been established. We, therefore, were motivated to develop a software environment for building such integrative models based on gene sets, and running simulations to conduct experiments in silico.

RESULTS

E-CELL, a modeling and simulation environment for biochemical and genetic processes, has been developed. The E-CELL system allows a user to define functions of proteins, protein-protein interactions, protein-DNA interactions, regulation of gene expression and other features of cellular metabolism, as a set of reaction rules. E-CELL simulates cell behavior by numerically integrating the differential equations described implicitly in these reaction rules. The user can observe, through a computer display, dynamic changes in concentrations of proteins, protein complexes and other chemical compounds in the cell. Using this software, we constructed a model of a hypothetical cell with only 127 genes sufficient for transcription, translation, energy production and phospholipid synthesis. Most of the genes are taken from Mycoplasma genitalium, the organism having the smallest known chromosome, whose complete 580 kb genome sequence was determined at TIGR in 1995. We discuss future applications of the E-CELL system with special respect to genome engineering.

AVAILABILITY

The E-CELL software is available upon request.

SUPPLEMENTARY INFORMATION

The complete list of rules of the developed cell model with kinetic parameters can be obtained via our web site at: http://e-cell.org/.

Antibacterial activity of lactoferrin and a pepsin-derived lactoferrin peptide fragment

Although the antimicrobial activity of lactoferrin has been well described, its mechanism of action has been poorly characterized. Recent work has indicated that in addition to binding iron, human lactoferrin damages the outer membrane of gram-negative bacteria. In this study, we determined whether bovine lactoferrin and a pepsin-derived bovine lactoferrin peptide (lactoferricin) fragment have similar activities. We found that both 20 microM bovine lactoferrin and 20 microM lactoferricin release intrinsically labeled [3H]lipopolysaccharide ([3H]LPS) from three bacterial strains, Escherichia coli CL99 1-2, Salmonella typhimurium SL696, and Salmonella montevideo SL5222. Under most conditions, more LPS is released by the peptide fragment than by whole bovine lactoferrin. In the presence of either lactoferrin or lactoferricin there is increased killing of E. coli CL99 1-2 by lysozyme. Like human lactoferrin, bovine lactoferrin and lactoferricin have the ability to bind to free intrinsically labeled [3H]LPS molecules. In addition to these effects, whereas bovine lactoferrin was at most bacteriostatic, lactoferricin demonstrated consistent bactericidal activity against gram-negative bacteria. This bactericidal effect is modulated by the cations Ca2+, Mg2+, and Fe3+ but is independent of the osmolarity of the medium. Transmission electron microscopy of bacterial cells exposed to lactoferricin show the immediate development of electron-dense "membrane blisters." These experiments offer evidence that bovine lactoferrin and lactoferricin damage the outer membrane of gram-negative bacteria. Moreover, the peptide fragment lactoferricin has direct bactericidal activity. As lactoferrin is exposed to proteolytic factors in vivo which could cleave the lactoferricin fragment, the effects of this peptide are of both mechanistic and physiologic relevance.

Potent antibacterial peptides generated by pepsin digestion of bovine lactoferrin

The antibacterial properties of enzymatic hydrolysates of bovine lactoferrin were examined to determine whether active peptides are produced from this protein. Hydrolysates prepared by cleavage of lactoferrin with porcine pepsin, cod pepsin, or acid protease from Penicillium duponti showed strong activity against Escherichia coli O111, whereas hydrolysates produced by trypsin, papain, or other neutral proteases were much less active. Low molecular weight peptides generated by porcine pepsin cleavage of lactoferrin showed broad-spectrum antibacterial activity, inhibiting the growth of a number of Gram-negative and Gram-positive species, including strains that were resistant to native lactoferrin. The antibacterial potency of the hydrolysate was at least eightfold greater than that of undigested lactoferrin with all strains tested. The active peptides retained their activity in the presence of added iron, unlike native lactoferrin. The effect of the hydrolysate was bactericidal as indicated by a rapid loss of viability of E. coli O111. The lactoferrin hydrolysate described in the present study has commercial value as a natural preservative agent for use in foods and cosmetics, and as a functional component of new clinical foods for prevention or treatment of gastrointestinal disease.

Retrograde transvenous obliteration of gastric varices

PURPOSE

To evaluate the clinical efficacy, techniques, and complications associated with balloon-occluded retrograde transvenous obliteration of gastric varices.

MATERIALS AND METHODS

Between December 1994 and November 1997, balloon-occluded retrograde transvenous obliteration was performed on 20 patients with gastric varices in danger of rupture and with gastrorenal shunts; three patients also had hepatic encephalopathy. The sclerosant was injected into the gastric varices during balloon occlusion. The degree of progression of the gastric varices and of collateral veins was classified into five grades, with grade 1 being least progression and grade 5 most progression; collateral veins that had developed were treated with embolization. Follow-up consisted of fiberoptic endoscopy and computed tomography.

RESULTS

Technical success was achieved in all patients. Occlusion of collateral veins was essential for the occlusion of gastric varices with a grade greater than grade 2. The clinical symptoms of hepatic encephalopathy in the three patients improved remarkably. Follow-up endoscopy 3 months after the procedure revealed the disappearance of gastric varices in 15 patients and reduced variceal size in five. During the follow-up period, 19 patients had no recurrence of gastric varices; three patients had aggravation of the esophageal varices.

CONCLUSION

Balloon-occluded retrograde transvenous obliteration is a feasible alternative to a transjugular intrahepatic portosystemic shunt for patients with large gastrorenal shunts or hepatic encephalopathy (or both).

The cerebrospinal-fluid soluble form of Alzheimer's amyloid beta is complexed to SP-40,40 (apolipoprotein J), an inhibitor of the complement membrane-attack complex

The amyloid fibrils deposited in Alzheimer's neuritic plaque cores and cerebral blood vessels are mainly composed of aggregated forms of a unique peptide, 39-42 amino acids long, named amyloid beta (A beta). A similar, although soluble, A beta ('sA beta') has been identified in cerebrospinal fluid, plasma and cell supernatants, indicating that it is normally produced by proteolytic processing of its precursor protein, amyloid precursor protein (APP). Using direct binding experiments we have isolated and characterized an 80 kDa circulating protein that specifically interacts with a synthetic peptide identical with A beta. The protein was unmistakably identified as SP-40,40 or ApoJ, a cytolytic inhibitor and lipid carrier, by means of amino acid sequence and immunoreactivity with specific antibodies. Immunoprecipitation with anti-SP-40,40 retrieved soluble A beta from cerebrospinal fluid, indicating that the interaction occurs in vivo.

Effectiveness of assistive technology and environmental interventions in maintaining independence and reducing home care costs for the frail elderly. A randomized controlled trial

CONTEXT

Home environmental interventions (EIs) and assistive technology (AT) devices have the potential to increase independence for community-based frail elderly persons, but their effectiveness has not been demonstrated.

OBJECTIVE

To evaluate a system of AT-EI service provision designed to promote independence and reduce health care costs for physically frail elderly persons.

DESIGN

Randomized controlled trial.

SETTING AND PARTICIPANTS

A total of 104 home-based frail elderly persons living in western New York were assigned to 1 of 2 groups (52 treatment, 52 control).

INTERVENTION

All participants underwent a comprehensive functional assessment and evaluation of their home environment. Participants in the treatment group received AT and EIs based on the results of the evaluation. The control group received "usual care services."

MAIN OUTCOME MEASURES

Functional status as measured by the Functional Independence Measure (FIM) and the Craig Handicap Assessment and Reporting Technique; pain as measured by the Functional Status Instrument; and health care costs including the costs.

RESULTS

After the 18-month intervention period, the treatment groups showed significant decline for FIM total score and FIM motor score, but there was significantly more decline for the control group. Functional Status Instrument pain scores increased significantly more for the control group. In a comparison of health care costs, the treatment group expended more than the control group for AT and EIs. The control group required significantly more expenditures for institutional care. There was no significant difference in total in-home personnel costs, although there was a large effect size. The control group had significantly greater expenditures for nurse visits and case manager visits.

CONCLUSION

The frail elderly persons in this trial experienced functional decline over time. Results indicate rate of decline can be slowed, and institutional and certain in-home personnel costs reduced through a systematic approach to providing AT and EIs.

Isolation from human erythrocytes of a new membrane protein which inhibits the formation of complement transmembrane channels

A protein which inhibited complement channel formation was isolated from extracts of papain-digested human erythrocyte membranes using DEAE-Sephacel, Bio-Gel A0.5m column chromatographies, and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by transfer to nitrocellulose paper and elution with 2% NP-40 solution. The purified protein showed a molecular weight of 18 kDa, and efficiently inhibited hemolysis of EC5-7 cells with C8 and C9, but did not show any decay-accelerating activity to C5 convertase. Immunochemical analysis of native membranes after sodium dodecyl sulfate-polyacrylamide gel electrophoresis using the antibody against this protein gave a single band having the same mobility as this protein; papain did not eliminate a significant portion of this protein.

Specific receptors for atrial natriuretic factor (ANF) in cultured vascular smooth muscle cells of rat aorta

Specific binding site for atrial natriuretic factor (ANF), a potent natriuretic and vasorelaxant polypeptide recently isolated from mammalian atria, was studied in cultured vascular smooth muscle cells (VSMC) of the rat aorta. Binding studies of 125I-labeled-synthetic alpha-human natriuretic peptide (alpha-hANP) revealed the presence of a non-interacting, single class of high affinity binding sites for alpha-hANP on VSMC in culture: the apparent dissociation constant (Kd) was approximately 1-2 X 10(-9)M and the number of maximal binding sites was approximately 200,000-300,000 sites/cell. A variety of vasoactive substances and other polypeptide hormones did not affect the binding of 125I-labeled-alpha-hANP to its binding sites. alpha-hANP significantly increased the concentrations of intracellular cyclic GMP in VSMC in a dose-dependent manner (3.2 X 10(-9)-1.6 X 10(-7)M). These data indicate that the specific receptor for ANF is present in VSMC and suggest that intracellular cyclic GMP may be involved in its vasorelaxant effect.

Bifidobacterium longum, a lactic acid-producing intestinal bacterium inhibits colon cancer and modulates the intermediate biomarkers of colon carcinogenesis

The human colon can be described as a complex microbial ecosystem, comprising several hundred bacterial species. Some of these enteric bacteria are beneficial to the host and have been shown to exert antimutagenic and anticarcinogenic properties. We have investigated the colon tumor inhibitory activity of Bifidobacterium longum, a lactic acid-producing enterobacterium. The modifying effects of this lactic culture on colonic mucosal and/or tumor cell proliferation, ODC activity and ras-p21 oncoprotein expression in colon carcinogenesis were also analyzed. Male F344 rats were fed a modified AIN-76A diet containing 0 or 2% lyophilized cultures of B. longum and s.c. administered azoxymethane (AOM) dissolved in normal saline at a dose of 15 mg/kg body wt, once weekly for 2 weeks. Vehicle controls received an equal volume of normal saline s.c. Animals were maintained on control or experimental diets until termination of the study. Animals intended for analysis of cell proliferation were killed 20 weeks after the second AOM injection, whereas animals intended for colon tumor analysis and measurement of ODC activity and ras-p21 expression were killed 40 weeks after the last AOM injection. The data demonstrate that dietary administration of lyophilized cultures of B. longum resulted in significant suppression of colon tumor incidence and tumor multiplicity and also reduced tumor volume. Results also revealed that ingestion of B. longum significantly inhibited AOM-induced cell proliferation, ODC activity and expression of ras-p21 oncoprotein. Data suggest that oral administration of probiotic B. longum exerts strong antitumor activity, as indicated by modulation of the intermediate biomarkers of colon cancer, and consequently reduced tumor outcome.

Does hyperuricemia affect mortality? A prospective cohort study of Japanese male workers

A positive association between hyperuricemia and cardiovascular disease has been reported, but no study has evidenced yet the precise role of serum uric acid in the development of cardiovascular disease. In addition, no epidemiological studies have so far documented a decreased risk of cancer among people with hyperuricemia, even though the antioxidant action of uric acid has recently been stressed to inhibit DNA damage. The present prospective cohort study investigates the relationship between hyperuricemia and health hazards in a Japanese working population. The subjects were 49,413 Japanese male railroad workers, aged 25-60 years at enrollment. Serum uric acid and other baseline data were provided by annual health-survey records from 1975 to 1982. The vital status of the subjects was traced until the end of 1985 for those who remained alive. During an average 5.4-year study period, 984 deaths were recorded. Those with serum uric acid over 8.5 mg/dl showed elevated relative risks (RRs) of death in all causes (RR 1.62, p<0.01), coronary heart disease ( RR 1.52), stroke (RR 2.33, p<0.01), hepatic disease (RR 3.58, p<0.01), and renal failure ( RR 8.52, p<0.01), as compared with those with serum uric acid levels of 5.0-6.4mg/dl. The RR of death in all causes still remains statistically significant when adjusted by age and serum total cholesterol (2.00, p<0.01), age and alcohol intake (1.85, p<0.001), age and smoking (1.69, p<0.001), age and gout treatment (1.61, p<0.05), and also age and BMI (1.50, p< 0.05). On the other hand, the RR of all causes decreased but was still above 1.0 when adjusted by age and blood glucose (1.62), age and systolic blood pressure (1.32), age and GOT (1.23), and also age and history of cardiovascular disease (1.17). These results showed that hyperuricemia has a strong association with the RRs of death in all causes, coronary heart disease, stroke, hepatic disease and renal failure, and indicated that serum uric acid seems to be a considerable risk factor for reduced life expectancy.

Sex-specific relevance of diabetes to occlusive vascular and other mortality: a collaborative meta-analysis of individual data from 980 793 adults from 68 prospective studies

BACKGROUND

Several studies have shown that diabetes confers a higher relative risk of vascular mortality among women than among men, but whether this increased relative risk in women exists across age groups and within defined levels of other risk factors is uncertain. We aimed to determine whether differences in established risk factors, such as blood pressure, BMI, smoking, and cholesterol, explain the higher relative risks of vascular mortality among women than among men.

METHODS

In our meta-analysis, we obtained individual participant-level data from studies included in the Prospective Studies Collaboration and the Asia Pacific Cohort Studies Collaboration that had obtained baseline information on age, sex, diabetes, total cholesterol, blood pressure, tobacco use, height, and weight. Data on causes of death were obtained from medical death certificates. We used Cox regression models to assess the relevance of diabetes (any type) to occlusive vascular mortality (ischaemic heart disease, ischaemic stroke, or other atherosclerotic deaths) by age, sex, and other major vascular risk factors, and to assess whether the associations of blood pressure, total cholesterol, and body-mass index (BMI) to occlusive vascular mortality are modified by diabetes.

RESULTS

Individual participant-level data were analysed from 980 793 adults. During 9·8 million person-years of follow-up, among participants aged between 35 and 89 years, 19 686 (25·6%) of 76 965 deaths were attributed to occlusive vascular disease. After controlling for major vascular risk factors, diabetes roughly doubled occlusive vascular mortality risk among men (death rate ratio [RR] 2·10, 95% CI 1·97-2·24) and tripled risk among women (3·00, 2·71-3·33; χ2 test for heterogeneity p<0·0001). For both sexes combined, the occlusive vascular death RRs were higher in younger individuals (aged 35-59 years: 2·60, 2·30-2·94) than in older individuals (aged 70-89 years: 2·01, 1·85-2·19; p=0·0001 for trend across age groups), and, across age groups, the death RRs were higher among women than among men. Therefore, women aged 35-59 years had the highest death RR across all age and sex groups (5·55, 4·15-7·44). However, since underlying confounder-adjusted occlusive vascular mortality rates at any age were higher in men than in women, the adjusted absolute excess occlusive vascular mortality associated with diabetes was similar for men and women. At ages 35-59 years, the excess absolute risk was 0·05% (95% CI 0·03-0·07) per year in women compared with 0·08% (0·05-0·10) per year in men; the corresponding excess at ages 70-89 years was 1·08% (0·84-1·32) per year in women and 0·91% (0·77-1·05) per year in men. Total cholesterol, blood pressure, and BMI each showed continuous log-linear associations with occlusive vascular mortality that were similar among individuals with and without diabetes across both sexes.

INTERPRETATION

Independent of other major vascular risk factors, diabetes substantially increased vascular risk in both men and women. Lifestyle changes to reduce smoking and obesity and use of cost-effective drugs that target major vascular risks (eg, statins and antihypertensive drugs) are important in both men and women with diabetes, but might not reduce the relative excess risk of occlusive vascular disease in women with diabetes, which remains unexplained.

FUNDING

UK Medical Research Council, British Heart Foundation, Cancer Research UK, European Union BIOMED programme, and National Institute on Aging (US National Institutes of Health).

Killing of Candida albicans by lactoferricin B, a potent antimicrobial peptide derived from the N-terminal region of bovine lactoferrin

Candida albicans was found to be highly susceptible to inhibition and inactivation by lactoferricin B, a peptide produced by enzymatic cleavage of bovine lactoferrin. Effective concentrations of the peptide varied within the range of 18 to 150 micrograms/ml depending on the strain and the culture medium used. Its effect was lethal, causing a rapid loss of colony-forming capability. 14C-labeled lactoferricin B bound to C. albicans and the rate of binding appeared to be consistent with the rate of killing induced by the peptide. The extent of binding was diminished in the presence of Mg2+ or Ca2+ ions which acted to reduce its anticandidal effectiveness. Binding occurred optimally at pH 6.0 and killing was maximal near the same pH. Such evidence suggests the lethal effect of lactoferricin B results from its direct interaction with the cell surface. Cells exposed to lactoferricin B exhibited profound ultrastructural damage which appeared to reflect its induction of an autolytic response. These findings suggest that active peptides of lactoferrin could potentially contribute to the host defense against C. albicans.

Whole-cell simulation: a grand challenge of the 21st century

Study of the cell will never be complete unless its dynamic behavior is understood. The complex behavior of the cell cannot be determined or predicted unless a computer model of the cell is constructed and computer simulation is undertaken. Rapid accumulation of biological data from genome, proteome, transcriptome and metabolome projects can bring us to the point where it is no longer purely speculative to discuss how to construct virtual cells in silico. This article describes attempts to construct whole cell models. The E-CELL project has completed a couple of virtual cell models, and computer simulations have revealed some biological surprises.