Depressive symptomatology in pregnancy - a Singaporean perspective

This is a two-part study looking at depressive symptomatology in pregnancy in Singaporean women, and the associated demographic, and bio-psychosocial characteristics of women at risk of depressive illness. We validated the 10-item Centre for Epidemiological Studies-Depression scale amongst pregnant women, and then used this tool to identify depressive states in an antenatal cohort from the national maternity hospital. Amongst the sample population, the rate of depressive disorders is as high as one in five in the antepartum. The risk factors in the antepartum include being young, history of smoking, having past and current obstetric complications, frequent alcohol use and having medical problems.

Proton source size measurements in the eA-->e'ppX reaction

Two-proton correlations at small relative momentum q were studied in the eA(3He,4He,C,Fe)-->e(')ppX reaction at E(0)=4.46 GeV using the CLAS detector at Jefferson Lab. The enhancement of the correlation function at small q was found to be in accordance with theoretical expectations. Sizes of the emission region were extracted, and proved to be dependent on A and on the proton momentum. The size of the two-proton emission region for He was measured in eA reactions for the first time.

Hidden Floridian biodiversity: mitochondrial and nuclear gene trees reveal four cryptic species within the scorched mussel, Brachidontes exustus, species complex

The well-documented Floridian 'Gulf/Atlantic' marine genetic disjunction provides an influential example of vicariant cladogenesis along a continental coastline for major elements of a diverse nearshore fauna. We are engaged in a two-part study that aims to place this disjunction into a regional Caribbean Basin phylogenetic perspective using the scorched mussel Brachidontes exustus as an exemplar. Our first step, documented here, is to thoroughly characterize the genetic structure of Floridian scorched mussel populations using mitochondrial (mt) and nuclear markers. Both sets of markers recovered the expected disjunction involving sister clades distributed on alternate flanks of peninsular Florida and lineage-specific mt molecular clocks placed its origin in the Pliocene. The two sister clades had distinct population genetic profiles and the Atlantic clade appears to have experienced an evolutionarily recent bottleneck, although plots of the relative estimates of N through time are consistent with its local persistence through the last Ice Age Maximum. Our primary novel result, however, was the discovery that the Gulf/Atlantic disjunction represents but one of three cryptic, nested genetic discontinuities represented in Floridian scorched mussel populations. The most pronounced phylogenetic split distinguished the Gulf and Atlantic sister clades from two additional nested cryptic sister clades present in samples taken from the southern Florida tropical marine zone. Floridian populations of B. exustus are composed of four cryptic taxa, a result consistent with the hypothesis that the Gulf/Atlantic disjunction in this morphospecies is but one of multiple latent regional genetic breakpoints.

Functional analysis of the homoserine O-acetyltransferase gene and its identification as a selectable marker in Gibberella zeae

We used restriction enzyme-mediated integration (REMI) to identify a methionine auxotrophic mutant of Gibberella zeae, an important cereal pathogen. In addition to its methionine requirement, the G. zeae REMI mutant designated Z43R3912 showed pleiotropic phenotypes, including reduced virulence on host plants and lack of sexual development. Outcrossing of Z43R3912 with a mat1-1 deletion strain confirmed that the mutation of Z43R3912 was tagged with the hygromycin B resistance marker. The vector insertion site in Z43R3912 was identified within the ORF designated GzmetE, encoding a putative homoserine O-acetyltrasferase (HOA). Gene disruption analyses confirmed that GzmetE was responsible for the pleiotropic phenotypes of Z43R3912. Genetic complementation of the G. zeae methionine auxotroph with an intact copy of the Aspergillus nidulans metE and GzmetE genes suggests that the HOA gene can be used as a selectable marker for transformation of G. zeae.

Qualitative and quantitative PCR methods for detection of three lines of genetically modified potatoes

Qualitative and quantitative polymerase chain reaction (PCR) methods have been developed for the detection of genetically modified (GM) potatoes. The combination of specific primers for amplification of the promoter region of Cry3A gene, potato leafroll virus replicase gene, and potato virus Y coat protein gene allows to identify each line of NewLeaf, NewLeaf Y, and NewLeaf Plus GM potatoes. Multiplex PCR method was also established for the simple and rapid detection of the three lines of GM potato in a mixture sample. For further quantitative detection, the realtime PCR method has been developed. This method features the use of a standard plasmid as a reference molecule. Standard plasmid contains both a specific region of the transgene Cry3A and an endogenous UDP-glucose pyrophosphorylase gene of the potato. The test samples containing 0.5, 1, 3, and 5% GM potatoes were quantified by this method. At the 3.0% level of each line of GM potato, the relative standard deviations ranged from 6.0 to 19.6%. This result shows that the above PCR methods are applicable to detect GM potatoes quantitatively as well as qualitatively.

Achievement of insulin independence via pancreatic islet transplantation using a remote isolation center: a first-year review

BACKGROUND

Owing to advances in both immunosuppressive protocols and pancreatic islet isolation techniques, insulin independence has recently been achieved in type 1 insulin-dependent diabetics (IDDM) via pancreatic islet transplantation (PIT). Although the dissemination of immunosuppressive protocols is relatively easy, transferring the knowledge and expertise required to isolate a large number of quality human islets for transplantation is a far greater challenge. Therefore, in an attempt to centralize the critical islet processing needed for islet transplantation and to avoid the development of another islet processing center, we have established a collaborative islet transplant program between two geographically distant transplant centers.

PATIENTS AND METHODS

Eleven consecutive type 1 IDDM patients with a history of severe hypoglycemia and metabolic instability underwent PIT at the Methodist Hospital (TMH) in Houston, Texas, utilizing pancreatic islets isolated at the Diabetes Research Institute (DRI) at the University of Miami in Miami, Florida between January 1, 2002 and June 31, 2003. Forty-one pancreata have been procured in the Houston area and have subsequently been transported for isolation at the DRI following enzymatic ductal perfusion by the automated method (Ricordi chamber). Following purification the islets were immediately transported back to TMH in Houston and transplanted via percutaneous transhepatic portal infusion. Immunosuppression regimen consisted of sirolimus, tacrolimus, and daclizumab.

RESULTS

Following harvesting, donor pancreata arrived at the DRI for initiation of the isolation process within 6.5 hours of cross-clamping (median time 5.4 hours; range 4.8 to 6.5 hours). The islets were immediately transported back to TMH for final sterility and viability tests and transplanted via percutaneous transhepatic portal vein infusion. The harvesting of 41 pancreata has yielded a number of pancreatic islets sufficient for transplantation (>5000 IEQ/kg recipient body weight) 26 times (63% of harvested pancreata). Thus far, three patients have received three PITs and eight patients have received two PITs. Six remain insulin independent. All have experienced a decrease in serum hemoglobin A(1c) levels, and both basal and stimulated C-peptide levels have increased. There have been no major complications related to the procedure or the immunosuppressive regimen used.

CONCLUSIONS

Our series demonstrates that pancreatic islets isolated at a remote isolation center can successfully and safely be used for PIT and the achievement of insulin independence.

Deletion and complementation of the mating type (MAT) locus of the wheat head blight pathogen Gibberella zeae

Gibberella zeae, a self-fertile, haploid filamentous ascomycete, causes serious epidemics of wheat (Triticum aestivum) head blight worldwide and contaminates grain with trichothecene mycotoxins. Anecdotal evidence dating back to the late 19th century indicates that G. zeae ascospores (sexual spores) are a more important inoculum source than are macroconidia (asexual spores), although the fungus can produce both during wheat head blight epidemics. To develop fungal strains to test this hypothesis, the entire mating type (MAT1) locus was deleted from a self-fertile (MAT1-1/MAT1-2), virulent, trichothecene-producing wild-type strain of G. zeae. The resulting MAT deletion (mat1-1/mat1-2) strains were unable to produce perithecia or ascospores and appeared to be unable to mate with the fertile strain from which they were derived. Complementation of a MAT deletion strain by transformation with a copy of the entire MAT locus resulted in recovery of production of perithecia and ascospores. MAT deletion strains and MAT-complemented strains retained the ability to produce macroconidia that could cause head blight, as assessed by direct injection into wheat heads in greenhouse tests. Availability of MAT-null and MAT-complemented strains provides a means to determine the importance of ascospores in the biology of G. zeae and perhaps to identify novel approaches to control wheat head blight.

Urinary 8-hydroxydeoxyguanosine excretion in children before and after therapy for eradication of Helicobacter pylori infection

AIM

A number of reports have implicated oxygen free radicals in the pathogenesis of Helicobacter pylori (H. pylori)-associated disease. 8-hydroxydeoxyguanosine (8-OHdG) has recently been accepted as a sensitive marker for reflecting the oxidative DNA damage. However, there have been no previous studies comparing the changes in urinary 8-OHdG excretions before and after therapy for eradication of H. pylori infection, or to examine 8-OHdG excretions in children with H. pylori infection. The aim of this study was therefore to examine the DNA damage in gastric mucosal cells in children with H. pylori infection.

METHODS

Urinary 8-OHdG excretions were measured before and after therapy for eradication of H. pylori infection in 15 children diagnosed with the H. pylori infection and 13 parents who were also suffering from the same infection.

RESULTS

In both the children and their parents, no significant differences were found in urinary 8-OHdG excretions either before or after the eradication therapy. Furthermore, there was no significant difference in urinary 8-OHdG excretions between 8 children with peptic ulcers and 7 children without ulcers, either before or after the therapy.

CONCLUSION

These results suggest that measurement of urinary 8-OHdG levels is not useful for evaluation of the DNA damage in H. pylori-infected gastric mucosa in children.

Urinary 8-hydroxydeoxyguanosine excretion in children before and after therapy for eradication of Helicobacter pylori infection

AIM

A number of reports have implicated oxygen free radicals in the pathogenesis of Helicobacter pylori (H. pylori)-associated disease. 8-hydroxydeoxyguanosine (8-OHdG) has recently been accepted as a sensitive marker for reflecting the oxidative DNA damage. However, there have been no previous studies comparing the changes in urinary 8-OHdG excretions before and after therapy for eradication of H. pylori infection, or to examine 8-OHdG excretions in children with H. pylori infection. The aim of this study was therefore to examine the DNA damage in gastric mucosal cells in children with H. pylori infection.

METHODS

Urinary 8-OHdG excretions were measured before and after therapy for eradication of H. pylori infection in 15 children diagnosed with the H. pylori infection and 13 parents who were also suffering from the same infection.

RESULTS

In both the children and their parents, no significant differences were found in urinary 8-OHdG excretions either before or after the eradication therapy. Furthermore, there was no significant difference in urinary 8-OHdG excretions between 8 children with peptic ulcers and 7 children without ulcers, either before or after the therapy.

CONCLUSION

These results suggest that measurement of urinary 8-OHdG levels is not useful for evaluation of the DNA damage in H. pylori-infected gastric mucosa in children.

Shifting fungal reproductive mode by manipulation of mating type genes: obligatory heterothallism of Gibberella zeae

Fungi capable of sexual reproduction use heterothallic (self-sterile) or homothallic (self-fertile) mating strategies. In most ascomycetes, a single mating type locus, MAT, with two alternative forms (MAT1-1 and MAT1-2) called idiomorphs, controls mating ability. In heterothallic ascomycetes, these alternative idiomorphs reside in different nuclei. In contrast, most homothallic ascomycetes carry both MAT1-1 and MAT1-2 in a single nucleus, usually closely linked. An example of the latter is Gibberella zeae, a species that is capable of both selfing and outcrossing. G. zeae is a devastating cereal pathogen of ubiquitous geographical distribution, and also a producer of mycotoxins that threaten human and animal health. We asked whether G. zeae could be made strictly heterothallic by manipulation of MAT. Targeted gene replacement was used to differentially delete MAT1-1 or MAT1-2 from a wild-type haploid MAT1-1; MAT1-2 strain, resulting in MAT1-1; mat1-2, mat1-1; MAT1-2 strains that were self-sterile, yet able to cross to wild-type testers and, more importantly, to each other. These results indicated that differential deletion of MAT idiomorphs eliminates selfing ability of G. zeae, but the ability to outcross is retained. They also indicated that both MAT idiomorphs are required for self-fertility. To our knowledge, this is the first report of complete conversion of fungal reproductive strategy from homothallic to heterothallic by targeted manipulation of MAT. Practically, this approach opens the door to simple and efficient procedures for obtaining sexual recombinants of G. zeae that will be useful for genetic analyses of pathogenicity and other traits, such as the ability to produce mycotoxins.

Electrical Characterization of Metal-Molecule-Silicon Junctions

Direct assembly of molecules onto silicon surfaces is of particular interest for potential employment in hybrid organic-semiconductor devices. In the study we report here, aryl diazonium salts were used to assemble covalently bound molecular groups on a hydride-passivated, oxide-free n-type Si(111) surface. The reaction of 4-(trimethylsilylethynyl)benzenediazonium tetrafluoroborate generates a molecular layer of 4-(trimethylsilylethynyl)phenylene (TMS-EP) on the n++-Si(111) surface. The monolayer modifies the electrical properties of the interface and exhibits nonlinear current-voltage characteristics, as compared with the ohmic behavior observed from metal-n++-Si(111) junctions. The result of current-voltage measurements at variable temperatures (from 300 to 10 K) on samples made with the TMS-EP molecule does not show significant thermally-activated transport, indicating that tunneling is the dominant transport mechanism. The measured data is compared to a tunneling model.

Regulation of Th2 cytokine gene transcription

Because of the different functions of IL-4, IL-13 and IL-5, it would perhaps be surprising if common transcriptional mechanisms occur. However, because of the physical proximity of their genes within the human 5q locus, chromatin remodelling during T-cell differentiation may make transcription of all the genes permissible. If co-ordinate regulation were to take place, it might be argued that similar factors might be involved in expression of all of the cytokines. Emerging data on c-Maf and GATA3 regulation of IL-4 and IL-5 respectively argues that diverse proteins may be required for transcriptional activation. Alternatively, these factors may be responsible for regulating transcriptional competence, allowing fine control over generation of particular cytokines depending upon recognition of physiological cues. If competent for transcription, common factors, such as members of the NFAT and/or AP-1 families, may operate to regulate cytokine levels. To support this, we have recently identified a conserved palindrome located within the promoters of the different Th2-type cytokines, which acts as an enhancer of transcription. Central to the capacity to express Th2 cytokines is likely to be the ability to remodel chromatin at the locus. It remains to be determined whether a single factor, or combination of factors acts to regulate this event. It is also unclear what the boundaries of remodelling within the locus are, i.e. whether IL-4 and IL-13 may be within open chromatin and IL-5 in a closed environment, and whether there is a hierarchy which determines whether particular cytokines are preferentially expressed irrespective of competence.

Cytokine balance in kidney tissue from lupus nephritis patients

OBJECTIVE

To identify the balance of Th1/Th2 cytokine expression in the kidney and evaluate the difference in cytokine balance between patients with lupus nephritis WHO classes IV and V.

METHODS

The expression of the CD40 molecule on cultured human mesangial cells was assessed by flow cytometry after stimulation with interferon gamma (IFN-gamma) or other cytokines. Frozen sections of kidney tissue from 10 patients with lupus nephritis and two non-SLE patients (with minimal-change disease) were stained with monoclonal antibodies for interleukin (IL)-4, IL-10, IL-12, IFN-gamma, CD4, CD8, CD40, CD68 and CD40L.

RESULTS

CD40 expression of cultured mesangial cells was up-regulated by IFN-gamma, but was not down-regulated in the presence of the Th2 cytokines IL-4 and IL-10. In the glomeruli, CD40 expression and the ratios of IFN-gamma-/IL-10-, IL-12-/IL-4- and (IFN-gamma+IL-12)/(IL-4+IL-10)-positive cells were significantly higher in class IV than in class V lupus nephritis (P < 0.05). Also CD40, IFN-gamma and the activity index derived from the renal biopsy were closely correlated.

CONCLUSION

IFN-gamma may contribute to the pathogenesis of proliferative glomerulonephritis by the up-regulation of CD40 and the activation of the cellular immune response in human lupus.

Effects of n-3 polyunsaturated fatty acids on indomethacin-induced changes in eicosanoid production and blood flow in the gastric mucosa of rats

We investigated the effects of n-3 polyunsaturated fatty acids (PUFAs) on non-steroidal anti-inflammatory drug (NSAID)-induced changes in microcirculation and eicosanoid production in the gastrointestinal mucosa. We measured gastric mucosal blood flow using laser Doppler flowmetry, assessed the fatty acid composition in the mucosal phospholipids, and quantified the production of prostaglandin E2 (PGE2), leukotriene B4, and leukotriene C4 (LTB4 and C4) from the mucosa with the stimulation of calcium ionophore 20 min after an injection of indomethacin or vehicle in rats fed a diet containing different compositions of alpha-linolenic acid. Four weeks after the initiation of the test diet the arachidonic acid level in gastric mucosal phospholipids was significantly lower in the perilla group than in the other three groups. Conversely, alpha-linolenic acid and eicosapentaenoic acid (EPA) were significantly higher in the perilla group than in the other three groups. The percent of gastric mucosal blood flow in the three groups administered indomethacin were significantly lower than that in the control group injected with vehicle alone. The percent of gastric mucosal blood flow in the perilla group was significantly higher than that in the corn group. LTB4 and LTC4 production from the gastric mucosa in the soybean and corn groups were significantly higher than those in the control group, and the LTC4 production in the perilla group was significantly lower than that in the corn group. There were no significant differences in PGE2 production among the four groups. Our results suggest that alpha-linolenic acid affectively suppressed the indomethacin-induced decreases in gastric mucosal blood flow by increasing EPA and decreasing the levels of arachidonic acid and LTC4 in the gastric mucosa.