Reversal of lead-induced oxidative stress by chelating agent, antioxidant, or their combination in the rat

The influence of N-acetyl cysteine (NAC), an antioxidant, on the therapeutic efficacy of meso-2,3-dimercaptosuccinic acid (DMSA), a hydrophilic, and its ester, monoisoamyl 2,3-dimercaptosuccinate (MiADMS), a lipophilic, both soft tissue lead mobilizers, was investigated in lead-preexposed rats. The subsequent treatment of lead-exposed animals with DMSA, MiADMS, or NAC reversed the lead-induced alterations in blood delta-aminolevulinic acid dehydratase, catalase, malondialdehyde (MDA), reduced glutathione, oxidized glutathione, and brain MDA levels. The combined treatment with DMSA and NAC was more effective than that with MiADMS and NAC in enhancing the restoration of all these parameters indicative of lead-induced oxidative stress. These reversals were consistent with the lead-removing ability of DMSA and MiADMS but not that of NAC. As the reversal of these parameters by NAC was independent of its lead-mobilizing capability, this ought to be mainly due to its strong antioxidant property. The increase in blood and brain zinc levels upon lead exposure appears to be the result of the redistribution of endogenous zinc due to lead. Subsequent treatment with DMSA, MiADMS, NAC, or their combination decreased the brain zinc as its excretable complexes with a transient increase in blood zinc level. The ideal treatment of lead poisoning seems to be a combination of a lead chelator and an antioxidant.

Solution conformation of a rationally designed nonapeptide

Partial 'turn-helix' type modules comprised of LD and DL chiral beta-turns serving as potential helix nucleators have been connected with a view to designing a nascent 'helix-turn-helix' type structure. Conformation of the resultant peptide Boc-(D)Glu-Ala-Aib-Lys-Val-Pro-(D)Asp-Leu-Leu-NHMe has been described in both DMSO and water.

Some essential elements in maternal and cord blood in relation to birth weight and gestational age of the baby

Maternal and cord blood were collected from 54 Indian women at parturition and analyzed for Zn, Cu, and Fe by flame atomic absorption spectrophotometry to determine the relationship between levels of these elements in mother's and infant's blood and maternal age, birth weight, and gestational age of the baby. The blood Zn level of mothers in the age group 24-28 yr was significantly higher than those of mothers in the age group of 18-23 yr (p<0.05). Similarly, mothers in the 24 to 28-yr group also had higher blood Fe level than mothers in the group 29-38 yr (p<0.05). The levels of Zn, Cu, and Fe were higher in the maternal blood and lower, but not significantly, in the cord blood of low-birth-weight babies than in those of normal-birth-weight babies. However, differences in the levels of Zn, Cu, and Fe between maternal and cord blood of the two birth-weight groups was statistically significant. There were no significant differences in the levels of the three elements in maternal or cord blood by the gestational age of the baby. A weak but significant correlation was found between the birth weight of the baby and the Fe level in the cord blood (r=0.26; p<0.05). Also, weak significant correlations were observed between gestational age of the baby and Fe (r=0.23; p<0.05) and Cu (r=0.31; p<0.05) levels in the cord blood. Although, there are many confounders of low birth weight and preterm deliveries, a diminished placental transfer of these essential elements could be one of the several etiological factors for low birth weight of newborns.

Synthesis of combinatorial libraries based on terpenoid scaffolds

Triterpenoid-based scaffolds betulinic acid (1a) and ursolic acid (1b), have been used for the generation of combinatorial libraries in parallel format using solid phase organic synthesis method. These templates have the potential for the synthesis and amplification of triterpenoid-based compounds with one and two-point diversity. This has been demonstrated by the synthesis of two small libraries comprising 18 derivatives each of betulinic acid and ursolic acid with structural diversity at C-3 and C-28 positions. The primary screening of antimalarial activity of these libraries against P. falciparum in vitro led to the identification of four compounds with 5 fold increase in the activity compared to betulinic and ursolic acids.

Histological and ultrastructural regulation in rabbit endometrial explants by estrogen in serum-free culture

A repertoire of hormonal signals including estrogen regulate the growth, differentiation, and functioning of diverse target tissues, including the ovary, the mammary gland, and skeletal tissue. A serum-free culture system derived from rabbit endometrium explants has been devised and is reported here to explore estrogen action in vitro. The system involves aseptically harvesting the uterus from a virgin rabbit, dissecting the endometrium, explanting it into 1- to 2-mm(3) pieces weighing approximately 1-2 mg each, and incubating these pieces in serum-free Medium-199. The culture is carried out for a period of 4 d in a humidified CO(2) incubator at 37 degrees C with 5% CO(2). The effect of extraneously added estrogen (1 microg/ml) was investigated by histological and ultrastructural procedures. It was observed that estrogen could induce specific changes, such as abundant mitochondria, rough endoplasmic reticulum, golgi complex, and intracellular collagen deposition, in both the epithelial and the fibroblast cell components of the explanted tissue. The study, therefore, indicates that the proposed system is an ideal tool for exploring and demonstrating estrogen responsiveness under in vitro conditions.

Methemoglobin reductase activity and in vitro sensitivity towards oxidant induced methemoglobinemia in swiss mice and beagle dogs erythrocytes

The NADH methemoglobin-reductase (EC 1.6.2.2) is mainly responsible for the maintenance of hemoglobin in its reduced and active state. The present study reveals the comparative status of this enzyme in normal Beagle dogs, rats, mice, mastomys and hamsters erythrocytes. The spectrophotometric and electrophoretic determinations showed that the above mentioned enzyme was deficient in the Beagle dog's erythrocytes. Furthermore, in vitro studies on the sensitivity of these rodents and Beagle dogs hemolysate towards oxidants, like primaquine and sodium nitrate, depicted a higher level of methemoglobin formation in the Beagle dogs hemolysate as compared to that of the rodent species. The deficiency of methemoglobin reductase in Beagle dogs erythrocytes could be responsible for their increased sensitivity towards oxidant induced methemoglobinemia.

Outcome following pancreaticoduodenectomy in patients undergoing preoperative biliary drainage

OBJECTIVE

To assess the role of preoperative biliary drainage (PBD) in the early outcome following pancreaticoduodenectomy (PD) for periampullary tumors.

DESIGN

Retrospective analysis of prospective database.

PATIENTS AND METHODS

121 PDs were performed for periampullary tumors between 1989 and 1998. 54 patients were operated following a PBD (group A) while 67 patients were operated without PBD. 50 patients underwent internal biliary drainage while 4 patients underwent external biliary drainage. Of the 67 patients without PBD, serum bilirubin was >10 mg% in 41 patients (group B) while 26 patients had bilirubin level of <10 mg% (group C).

RESULT

Patients were well matched for age, sex distribution, presence of medical risk factors, duration of surgery, operative blood loss and stage of disease. Group A patients had a higher incidence of wound infection (43 vs. 24%; p = 0.03), intra-abdominal abscess (28 vs. 15%; p = 0.06), pancreaticojejunal anastomotic leak (20 vs. 5%; p = 0.01) and overall infective complications (52 vs. 29%; p = 0.01) compared to group B patients, and a higher overall infective complication rate than group C patients (52 vs. 27%; p = 0.02). Group B patients had a higher incidence of intra-abdominal bleeding compared to group A (20 vs. 6%; p = 0.01) and group C patients (20 vs. 4%; p = 0.03). Reoperation rate was significantly higher in group B compared to group A patients (27 vs. 13%; p = 0.04). The mortality rates were not significantly different in the three groups.

CONCLUSION

Patients with jaundice (>10 mg%) have a higher risk of bleeding complications while those with PBD have more infective complications. PBD should be judicially employed in selected patients.

Simulated learning environments in anatomy and surgery delivered via the next generation internet

The Next Generation Internet (NGI) will provide high bandwidth, guaranteed Quality of Service, collaboration and security, features that are not available in today's Internet. Applications that take advantage of these features will need to build them into their pedagogic requirements. We present the Anatomy Workbench and the Surgery Workbench, two applications that require most of these features of the NGI. We used pedagogic need and NGI features to define a set of applications that would be difficult to operate on the current Internet, and that would require the features of the NGI. These applications require rich graphics and visualization, and extensive haptic interaction with biomechanical models that represent bony and soft tissue. We are in the process of implementing these applications, and some examples are presented here. An additional feature that we required was that the applications be scalable such that they could run on either on a low-end desktop device with minimal manipulation tools or on a fully outfitted high-end graphic computer with a realistic set of surgical tools. The Anatomy and Surgery Workbenches will be used to test the features of the NGI, and to show the importance of these new features for innovative educational applications.

UreC PCR based diagnosis of Helicobacter pylori infection and detection of cag A gene in gastric biopsies

Polymerase chain reaction assay using ureC gene specific primers for the detection of Helicobacter pylori in gastric biopsy specimens from 116 dyspeptic patients was compared with other routine invasive diagnostic methods (culture, rapid urease test [RUT] and histology). In parallel, gastric biospy specimens from 54 patients and their corresponding Helicobacter pylori isolates were subjected to PCR with cagA targeting primers using standard protocols. Helicobacter pylori were detected in 53%, 43%, 48% and 50% of patients by PCR, RUT, culture and histological examination respectively. Based on histology and culture positive and at least three test positive result, 44 (37%), 46 (39%) and 26 (22%), and 56 (48%), 52 (44%) and 8 (6%) patients were classified as Helicobacter pylori positive, negative and indeterminate respectively. The sensitivity and specificity of PCR assay was the highest-95% and 100% when compared with both culture and histology positive, and at least any three positive results respectively. The result of cagA positivity in 54 gastric biopsy specimens and their corresponding Helicobacter pylori isolates were identical; 18 of 20 (90%) duodenal ulcer patients and 23 of 28 (82%) patients with chronic gastritis and 2 (40%) of 5 patients with portal hypertension and one gastric biopsy specimens from gastric cancer patients were found to be cagA positive. PCR-based method to detect Helicobacter pylori and the virulence gene cag A directly from gastric biopsy specimens appears to be promising and can curtail the lengthy process of culture-based approaches. The procedure proved to be rapid and reliable and could be utilized for diagnostic purposes.

Elimination of 118 Da: a characteristic fragmentation in the tandem mass spectra of 11(15 --> 1)-abeo-taxanes

The mechanism of the elimination of 118 Da from 11(15-->1)-abeo-taxanes was elucidated with the help of the tandem mass spectra of [M + NH(4)](+) and [M + Li](+) ions and the corresponding D-exchanged species. The fragmentation is triggered by the initial loss of the C-10 substituent. Evidence was also obtained for the stepwise elimination of acetone and acetic acid. Acetone is eliminated from the C-1 hydroxyisopropyl group and acetic acid from either the C-9 or C-7 acetoxy groups. The presence of an additional acetoxy group at C-13 leads to the direct elimination of 118 Da from [M + NH(4)](+) and [M + Li](+) ions involving the C-13 acetoxy group.

Association of maternal blood pressure and hemoglobin level with organochlorines in human milk

Milk samples of women from the general population in Lucknow were analysed by gas-liquid chromatography to determine the concentration of organochlorine pesticides and their possible association with maternal characteristics. p,p'-DDT (dichloro diphenyltrichloroethane), p,p-DDE (dichloro diphenyltrichloroethylene), p,p'-DDD (dichloro diphenyl dichloroethane), alpha, beta gamma and delta isomers of hexachlorocyclohexane (HCH) and aldrin were detected. The calculated daily intake of DDT and HCH by the neonates exceeded their acceptable daily intake (ADI) set by the WHO. A statistically significant association was noted between alpha-HCH residues in milk and hemoglobin (Hb) level in maternal blood (P < 0.001). Also, there was a significant association between gamma-HCH and p,p'-DDT levels in milk and diastolic blood pressure of mother (P < 0.05). An apparent negative relationship between p,p'-DDE level in mother's milk and birthweight of the baby was also noticed (P < 0.05). These results highlight the need for periodic monitoring to determine organochlorine contamination in human milk and assess their impact on mother and on neonatal health.

Point mutation and polymorphism in Duchenne/Becker muscular dystrophy (D/BMD) patients

Duchenne and Becker muscular dystrophies (D/BMD) are caused by mutations in the dystrophin gene. Two-thirds of patients have large intragenic deletions or duplications and the remaining one-third have point mutations, small deletions or insertions. Point mutations are more difficult to detect due to the enormous size (2.4 Mb) of the gene and its large transcript (14 kb). In the present study, a total of 50 DNA samples from unrelated D/BMD (38 DMD and 12 BMD) patients who did not show intragenic deletions by multiplex PCR, were analyzed for detection of point mutations. Single stranded conformation analysis and heteroduplex analysis observed electrophoretic mobility shifts in one (BMD) and two (DMD and BMD) patients, respectively. The mobility shift and heteroduplexes were observed in exon 17 in all of the three patients. Sequencing of the amplified PCR products revealed a nucleotide change (-37 g to t) in the intronic region in two of the patients while a C2268T substitution in the exonic region in one. Mutation database search for D/BMD mutations showed the nucleotide substitution in the exonic region as a novel change in the human dystrophin gene, which was not reported earlier. It resulted in an amino acid transition from threonine to methionine in the 687th position of the dystrophin protein. This novel substitution has been included in the mutation database of Leiden muscular dystrophy pages (http://www.dmd.nl) in the rare polymorphism/mutation category. The substituted nucleotide segregated with the disease phenotype in the family suggesting that it can be directly used for carrier detection and prenatal diagnosis without identification of disease causing mutation.

Manipulating mitochondrial DNA heteroplasmy by a mitochondrially targeted restriction endonuclease

Mutations in the mitochondrial DNA (mtDNA) can cause a variety of human diseases. In most cases, such mutations are heteroplasmic (i.e. mutated and wild-type mtDNA coexist) and a small percentage of wild-type sequences can have a strong protective effect against a metabolic defect. Because a genetic approach to correct mtDNA mutations is not currently available, the ability to modulate heteroplasmy would have a major impact in the phenotype of many patients with mitochondrial disorders. We show here that a restriction endonuclease targeted to mitochondria has this ability. A mitochondrially targeted PstI degraded mtDNA harboring PstI sites, in some cases leading to a complete loss of mitochondrial genomes. Recombination between DNA ends released by PstI was not observed. When expressed in a heteroplasmic rodent cell line, containing one mtDNA haplotype with two sites for PstI and another haplotype having none, the mitochondrial PstI caused a significant shift in heteroplasmy, with an accumulation of the mtDNA haplotype lacking PstI sites. These experiments provide proof of the principle that restriction endonucleases are feasible tools for genetic therapy of a sub-group of mitochondrial disorders. Although this approach is limited by the presence of mutation-specific restriction sites, patients with neuropathy, ataxia and retinitis pigmentosa (NARP) could benefit from it, as the T8399G mutation creates a unique restriction site that is not present in wild-type human mitochondrial DNA.

Three paths of adult development: conservers, seekers, and achievers

This study examined the development of individuals whose motivations and skills led them to develop in different but equally positive ways. C. D. Ryff's (1989) scales for Environmental Mastery (EM) and Personal Growth (PG) were used to identify three configurations of positive mental health in 111 women of the Mills Longitudinal Study: Achievers, high on both scales; Conservers, high on EM, low on PG; and Seekers, high on PG, low on EM. Each pattern showed a distinctive profile of strengths on four criteria of maturity--competence, generativity, ego development, and wisdom--and each was predicted by distinctive features of positive and negative emotionality, identity processes, and change in self-control across 31 years of adulthood. Identity at age 43 mediated the influence of personality at age 21 in predicting positive mental health pattern at age 60.

A novel human cancer culture model for the study of prostate cancer

Research into molecular and genetic mechanisms underlying prostate carcinogenesis would be greatly advanced by in vitro models of prostate tumors representing primary tumors. We have successfully established an immortalized human prostate epithelial (HPE) cell culture derived from a primary tumor with telomerase. The actively proliferating early passaged RC-58T cells were transduced through infection with a retrovirus vector expressing the human telomerase catalytic subunit (hTERT). A high level of telomerase was detected in RC-58T/hTERT cells but not RC-58T cells. RC-58T/hTERT cells are currently growing well at passage 50, whereas RC-58T cells senesced at passage 7. RC-58T/hTERT cells exhibit transformed morphology. More importantly, these immortalized cells showed anchorage-independent growth as they formed colonies in soft agar and grew above the agar layer. Expression of androgen-regulated prostate specific gene NKX3.1 and epithelial specific cytokeratin 8 (CK8) but not prostate specific antigen (PSA) and androgen receptor was detected in RC-58T/hTERT cells. Prostate stem cell antigen (PSCA) and p16 were also expressed in this cell line. RC-58T/hTERT cells showed growth inhibition when exposed to retinoic acid and transforming growth factor (TGF)-beta1 known potent inhibitors of prostate epithelial cell growth. A number of chromosome alterations were observed including the loss of chromosomes Y, 3p, 10p, 17p, 18q and the gain of chromosomes 16 and 20. These results demonstrate that this primary tumor-derived HPE cell line retained its transformed phenotypes and should allow studies to elucidate molecular and genetic alterations involved in prostate cancer. This is the first documented case of an established human prostate cancer cell line from a primary tumor of a prostate cancer patient with telomerase.

Mutational analysis of zinc resistance in Pseudomonas putida strain S4

The genes for resistance to any essential metal ion are generally tightly regulated. In Pseudomonas putida strain S4, a multiple metal-resistant strain, mutational analysis gave strong evidence to the presence of the same for the expression of Zn resistance. Zn-sensitive mutants showed a lower MTC of Zn and expressed the Zn resistance genes with a lower efficacy. Non-complementation between these mutants suggests that they are possibly involved in the same function. Altered response to Zn of these mutants assisted in predicting the involvement of a repressor protein regulating the expression of Zn resistance genes. Zn hypersensitive mutant, on the other hand, appears to have an unregulated Zn uptake. This seems to provide the sensor component in the regulation. Zn resistance in strain S4 consists of three steps, viz., uptake, efflux, and binding, which are shared by a Zn homeostasis mechanism as well.

Trends in biomarker research for cancer detection

A key challenge in cancer control and prevention is detection of the disease as early as possible, enabling effective interventions and therapies to contribute to reduction in mortality and morbidity. Biomarkers are important as molecular signposts of the physiological state of a cell at a specific time. Active genes, their respective protein products, and other organic chemicals made by the cell create these signposts. As a normal cell progresses through the complex process of transformation to a cancerous state, biomarkers could prove vital for the identification of early cancer and people at risk of developing cancer. We discuss current research into the genetic and molecular signatures of cells, including microsatellite instability, hypermethylation and single-nucleotide polymorphisms. The use of genomic and proteomic high-throughput technology platforms to facilitate detection of early cancer by means of biomarkers, and issues on the analysis, validation, and predictive value of biomarkers based on these technologies are also discussed. We report on recent advances in identifying sources of biomarkers that can be accessed by noninvasive techniques, such as buccal-cell isolates, as well as traditional sources such as serum or plasma. We also focus on the work of the Early Detection Research Network at the National Cancer Institute, harnessing expertise from leading national and international institutions, to identify and validate biomarkers for the detection of precancerous and cancerous cells in assessing risk of cancer. The network also has a role in linking discovery to process development, resulting in early detection tests and clinical assessment.

Conformation of N-terminal HIV-1 Tat (fragment 1-9) peptide by NMR and MD simulations

The N-terminal portion of HIV-1 Tat covering residues 1-9 is a competitive inhibitor of dipeptidyl peptidase IV (DP IV). We have used 1H NMR techniques, coupled with molecular dynamics methods, to determine the conformation of this peptide in the three diverse media: DMSO-d6, water (pH 2.7) and 40% HFA solution. The results indicate that in both DMSO-d6 and HFA the peptide has a tendency to acquire a type I beta-turn around the segment Asp5-Pro6-Asn7-IIe8. The N-terminal end is seen to be as a random coil. In water, the structure is best described as a left-handed polyproline type II (PPII) helix for the mid segment region Asp2 to Pro6. The structures obtained in this study have been compared with an earlier report on Tat (1-9).