Student screening for inherited blood disorders in Bahrain

In Bahrain and neighbouring countries inherited disorders of haemoglobin, i.e. sickle-cell disease, thalassaemias and glucose-6-phosphate dehydrogenase (G6PD) deficiency, are common. As part of the National Student Screening Project to determine the prevalence of genetic blood disorders and raise awareness among young Bahrainis, we screened 11th-grade students from 38 schools (5685 students), organized lectures and distributed information about these disorders. Haemoglobin electrophoresis, high performance liquid chromatography, blood grouping and G6PD deficiency testing were performed. Prevalences were: 1.2% sickle-cell disease; 13.8% sickle-cell trait; 0.09% beta-thalassaemia; 2.9% beta-thalassaemia trait; 23.2% G6PD deficiency; 1.9% G6PD deficiency carrier. Health education, carrier screening and premarital counselling remain the best ways to reduce disease incidence with potentially significant financial savings and social and health benefits.

The contribution of type of daily activity to loading across the hip and knee joints in the elderly

OBJECTIVE

In the elderly, we evaluated loading across the hip or knee joints during different daily activities.

METHODS

Elderly people drawn from the community entering an exercise study underwent a full kinetic and kinematics analysis of five different activities, standing, walking, arising from a chair, going downstairs and bending over. Inverse dynamic equations were used to compute forces and torques across the knees and hips during all of these activities.

RESULTS

132 elderly people, mean age 75, participated. Compressive forces across the knees and hips were, by far, the greatest vector forces and were highest during stair descent and, to a lesser extent, during walking. Compressive forces were lowest during standing. The highest moments were flexion and adduction moments, and these were maximal during stair descent.

CONCLUSION

Of the five activities we studied, descending stairs was associated with the highest calculated forces and torques across the knees and hips, and that may account for its tendency to cause joint symptoms and for its possible association with osteoarthritis incidence.

Topical 0.2 percent glyceryl trinitrate ointment has a short-lived effect on resting anal pressure

PURPOSE

Glyceryl trinitrate ointment applied to the anal verge lowers anal resting pressure, but its duration of action is uncertain. This study investigated the effect and duration of action of 0.2 percent glyceryl trinitrate on anal resting pressure and hemodynamic parameters.

METHODS

A total of 15 volunteers, 9 male, with a median age of 30 (range, 20-71) years, underwent continuous static anal manometry using a solid state catheter for ten minutes before and two hours after applying 0.2 percent glyceryl trinitrate ointment to the anoderm with a gloved finger. Pulse and blood pressure were recorded every 15 minutes.

RESULTS

A significant reduction in maximal anal resting pressure compared with preglyceryl trinitrate values was observed at 15, 30, 45, 60, and 90 minutes after application, but no significant difference thereafter. There was no significant change in pulse during the study. Systolic and diastolic blood pressures dropped significantly after application of glyceryl trinitrate, but had recovered and were not significantly different from original values after 90 minutes. A significant fall in blood pressure did not correlate with the onset or duration of side effects.

CONCLUSIONS

Continuous static manometry (as opposed to interval measurements reported in previous studies) demonstrates that 0.2 percent glyceryl trinitrate ointment significantly lowers anal resting pressure, but only for 90 minutes. Twice daily application of topical 0.2 percent glyceryl trinitrate heals two-thirds of fissures after eight weeks, but its apparently short duration of action may indicate that more frequent application might heal more fissures, more rapidly.

Decomposition rates of isothiocyanate conjugates determine their activity as inhibitors of cytochrome p450 enzymes

Thiol conjugates of isothiocyanates (thiol-ITCs) are metabolites of ITCs formed in the mercapturic acid pathway in mammals. They are effective chemopreventive agents in mouse lung tumor bioassays and in other models. Thiol-ITCs are inhibitors of P450s, but it has not been determined if P450 inhibition is due to conjugates themselves or to parent ITCs released by deconjugation reactions. In studies of mechanism of chemopreventive action of thiol-ITCs, rates of deconjugation of Cys, GSH, and N-acetyl-L-cysteine (NAC) conjugates of benzyl isothiocyanate (BITC), phenethyl isothiocyanate (PEITC), 6-phenylhexyl isothiocyanate (PHITC), and sulforaphane (SFN), expressed as the first-order rate constant k(1) and the half-life of decomposition Dt(1/2), were measured in aqueous solutions at pH 7.4 and 37 degrees. The Dt(1/2)s for the Cys conjugates were severalfold shorter than the Dt(1/2)s for respective GSH conjugates, while the Dt(1/2)s for the NAC conjugates were the longest. Cleavage of thiol conjugates was pH dependent, much slower under acidic conditions than at pH 7.4. Inhibition of P450 enzymes by thiol-ITCs was followed using PROD (pentoxyresorufin O-dealkylation) for P450 2B1 and EROD (ethoxyresorufin O-dealkylation) for P450 1A1. The inhibition of PROD and EROD by aqueous thiol-ITCs increased with preincubation time and was roughly parallel to the extent of decomposition of the conjugate that had occurred, indicating that both potency of the respective parent ITC and the rate of reductive cleavage of the conjugate influenced enzyme inhibition. In the presence of 250-1000 microM GSH, comparable to physiological levels, rates of deconjugation of thiol-ITCs were markedly reduced; inhibition of PROD was also proportionately reduced. Slow rates of decomposition of thiol-ITCs anticipated in plasma and tissues suggests that inhibition of P450 enzymes involved in carcinogen activation by ITCs released from thiol-ITCs may not be a principal mechanism for their tumor inhibitory activity; other mechanisms probably contribute to their chemopreventive activity.

The spectrum of pathogenic mutations in SPINK5 in 19 families with Netherton syndrome: implications for mutation detection and first case of prenatal diagnosis

The Comèl-Netherton syndrome is an autosomal recessive multisystemic disorder characterized by localized or generalized congenital ichthyosis, hair shaft abnormalities, immune deficiency, and markedly elevated IgE levels. Life-threatening complications during infancy include temperature and electrolyte imbalance, recurrent infections, and failure to thrive. To study the clinical presentations of the Comèl-Netherton syndrome and its molecular cause, we ascertained 19 unrelated families of various ethnic backgrounds. Results of initial linkage studies mapped the Comèl-Netherton syndrome in 12 multiplex families to a 12 cM interval on 5q32, thus confirming genetic homogeneity of Comèl-Netherton syndrome across families of different origins. The Comèl-Netherton syndrome region harbors the SPINK5 gene, which encodes a multidomain serine protease inhibitor (LEKTI) predominantly expressed in epithelial and lymphoid tissues. Recently, recessive mutations in SPINK5 were identified in several Comèl-Netherton syndrome patients from consanguineous families. We used heteroduplex analysis followed by direct DNA sequencing to screen all 33 exons and flanking intronic sequences of SPINK5 in the affected individuals of our cohort. Mutation analysis revealed 17 distinct mutations, 15 of which were novel, segregating in 14 Comèl-Netherton syndrome families. The nucleotide changes included four non-sense mutations, eight small deletions or insertions leading to frameshift, and five splice site defects, all of which are expected to result in premature terminated or altered translation of SPINK5. Almost half of the mutations clustered between exons 2 and 8, including two recurrent mutations. Genotype-phenotype correlations suggested that homozygous nucleotide changes resulting in early truncation of LEKT1 are associated with a severe phenotype. For the first time, we used molecular data to perform prenatal testing, thus demonstrating the feasibility of molecular diagnosis in the Comèl-Netherton syndrome.

Inhibition of intra-abdominal adhesions: a comparison of hemaseel APR and cryoprecipitate fibrin glue

Our previous studies demonstrated fibrin glue (FG) prepared from cryoprecipitate (cryo) inhibits intra-abdominal adhesions in rats. A new FG, Hemaseel APR, is Food and Drug Administration (FDA) approved for hemostasis during cardiac surgery and splenic trauma. This study was undertaken to determine if Hemaseel FG prevents intra-abdominal adhesions, and to compare it to cryo FG. Forty-five rats underwent laparotomy. Bilateral peritoneal-muscular defects were created. Polypropylene mesh was sewn into each defect with a running silk suture. The bowel was abraded with gauze. The rats were then randomized to mesh covered with Hemaseel FG, cryo FG, or control. On postoperative day 7, the severity of adhesions were graded by percentage of mesh covered by adhesion (0-100%) and degree of adhesion (0-3). The mean percentage of mesh covered by adhesion was 9% for Hemaseel FG, 43% for cryo FG (p = .005), and 65% for the controls (p < .0001). The mean density adhesion score was 0.5 for Hemaseel FG, 1.2 for cryo FG (p = .04), and 2.1 for the controls (p < .0001). In the Hemaseel FG group, 77% of patches had no adhesions, compared with 37% in the cryo FG group (p = .004) and 13% in the controls (p < .0001). Thus, Hemaseel FG significantly decreases intra-abdominal adhesions, and is more effective than cryo FG.

Base sequence dependence of in vitro translesional DNA replication past a bulky lesion catalyzed by the exo- Klenow fragment of Pol I

The effects of base sequence, specifically different pyrimidines flanking a bulky DNA adduct, on translesional synthesis in vitro catalyzed by the Klenow fragment of Escherichia coli Pol I (exo(-)) was investigated. The bulky lesion was derived from the binding of a benzo[a]pyrene diol epoxide isomer [(+)-anti-BPDE] to N(2)-guanine (G*). Four different 43-base long oligonucleotide templates were constructed with G* at a site 19 bases from the 5'-end. All bases were identical, except for the pyrimidines, X or Y, flanking G* (sequence context 5'-.XGY., with X, Y = C and/or T). In all cases, the adduct G* slows primer extension beyond G* more than it slows the insertion of a dNTP opposite G* (A and G were predominantly inserted opposite G, with A > G). Depending on X or Y, full lesion bypass differed by factors of approximately 1.5-5 ( approximately 0.6-3.0% bypass efficiencies). A downstream T flanking G on the 5'-side instead of C favors full lesion bypass, while an upstream C flanking G* is more favorable than a T. Various deletion products resulting from misaligned template-primer intermediates are particularly dominant ( approximately 5.0-6.0% efficiencies) with an upstream flanking C, while a 3'-flanking T lowers the levels of deletion products ( approximately 0.5-2.5% efficiencies). The kinetics of (1) single dNTP insertion opposite G* and (2) extension of the primer beyond G* by a single dNTP, or in the presence of all four dNTPs, with different 3'-terminal primer bases (Z) opposite G* were investigated. Unusually efficient primer extension efficiencies beyond the adduct (approaching approximately 90%) was found with Z = T in the case of sequences with 3'-flanking upstream C rather than T. These effects are traced to misaligned slipped frameshift intermediates arising from the pairing of pairs of downstream template base sequences (up to 4-6 bases from G*) with the 3'-terminal primer base and its 5'-flanking base. The latter depend on the base Y and on the base preferentially inserted opposite the adduct. Thus, downstream template sequences as well as the bases flanking G* influence DNA translesion synthesis.

Concordant p53 and mdm-2 protein expression in vulvar squamous cell carcinoma and adjacent lichen sclerosus

To determine if carcinogenic events in vulvar skin precede the onset of morphologic atypia, the authors investigated for derangements in DNA content, cell proliferation, and cell death in vulvar carcinomas and surrounding skin in 140 samples of tumor and surrounding skin collected from 35 consecutive vulvectomy specimen for squamous cell carcinoma (SCC) or vulvar intraepithelial neoplasia (VIN) 3. Vulvar non-cancer excisions were used as controls. Investigations consisted of histologic classification and measurement of 9 variables--epidermal thickness (acanthosis and rete ridge length), immunolabeling index (LI) for 3 proteins (p53 protein, Ki-67, and mdm-2), pattern of p53 expression (dispersed vs. compact), DNA content index, and presence of aneuploidy by image analysis and apoptotic rate by Apotag labeling. Significant positive correlations were found for all nine variables studied versus increasing histologic severity in two proposed histologic stepwise models of vulvar carcinogenesis (lichen sclerosus (LS) and VIN 3 undifferentiated associated SCC groups). High p53 LI (>25) and the compact pattern of p53 expression (suspected oncoprotein) significantly correlated with LS and its associated vulvar samples compared with samples not associated with LS (P < or = 0.001). Furthermore, p53 LI, mdm-2 LI, and pattern of p53 expression were concordant between patient matched samples of LS and SCC. In addition, mdm-2 LI significantly correlated with dispersed pattern p53 LI suggesting a response to wild-type p53 protein accumulation. These findings support the hypothesis that neoplastic transformation occurs in sequential steps and compromises proteins involved in the cell cycle control. Concordance of p53 and mdm-2 protein expression in LS and adjacent SCC provides evidence that LS can act as a precursor lesion in the absence of morphologic atypia. Overexpression of mdm-2 with stabilization and inactivation of p53 protein may provide an alternate pathway for vulvar carcinogenesis.

Patterns and predictors of hospitalisation in first-episode psychosis. Prospective cohort study

BACKGROUND

Little is known about predictors of hospitalisation in patients with first-episode psychosis.

AIMS

To identify the pattern and predictors of hospitalisation of patients with a first psychotic episode making their first contact with specialist services.

METHOD

Three-year follow-up of a cohort of 166 patients with a first episode of psychosis making contact with psychiatric services in Nottingham between June 1992 and May 1994.

RESULTS

Eighty-eight (53.0%) patients were admitted within 1 week of presentation; 32 (19.3%) were never admitted during the 3 years of follow-up. Manic symptoms at presentation were associated with an increased risk of rapid admission and an increased overall risk of admission; negative symptoms and a longer duration of untreated illness had an increased risk of late admission.

CONCLUSIONS

Community-oriented psychiatric services might only delay, rather than prevent, admission of patients with predominantly negative symptoms and a longer duration of untreated illness. First-episode studies based upon first admissions are likely to be subject to selection biases, which may limit their representativeness.

Metabolic activation of benzo[c]phenanthrene by cytochrome P450 enzymes in human liver and lung

The environmentally occurring polycyclic aromatic hydrocarbon (PAH) benzo[c]phenanthrene (B[c]PH) is a weak carcinogen in rodents. In contrast, the dihydrodiol-epoxides of B[c]PH are among the most carcinogenic PAH metabolites tested so far. In rodents, B[c]PH is predominantly metabolized to B[c]PH-5,6-dihydrodiol (B[c]PH-5,6-DH) and only to a minor extent to B[c]PH-3,4-DH, the proximate precursor of the highly potent ultimate carcinogen, B[c]PH-3,4-DH-1,2-epoxide. This might explain why in rodents B[c]PH is a weak carcinogen. However, little is known about human metabolism of B[c]PH. Using microsomal preparations from human liver and lung, we investigated the metabolic activation of B[c]PH. In contrast to the findings in experimental animals, human liver microsomes predominantly generated B[c]PH-3,4-DH and only to a minor extent B[c]PH-5,6-DH. Only one lung tissue sample was found to be metabolically active, producing B[c]PH-5,6-DH together with small amounts of B[c]PH-3,4-DH. Catalytic activities known to be associated with specific cytochrome P450 (P450) enzyme activities were determined and correlated with the spectrum of B[c]PH metabolites. The results indicate that B[c]PH-DH formation in human liver is mainly mediated by P450 1A2. Studies with P450 enzyme selective inhibitors confirmed these findings. Further support was obtained using preparations of the respective human recombinant P450 enzymes expressed in Escherichia coli and yeast. In addition to P450 1A2, P450 1B1 effectively mediated B[c]PH-metabolism. The umu-assay for induction of SOS repair response in Salmonella typhimurium TA 1535 pSK 1002 containing a umuC-lacZ reporter gene was used to study metabolic generation of genotoxic metabolites from B[c]PH-DHs in human microsomal preparations. B[c]PH-3,4-DH was activated by human liver microsomes to a potent genotoxic agent. Taken together, the results clearly demonstrate that human liver microsomes can effectively catalyze the biotransformation of B[c]PH into highly genotoxic metabolites. The results provide evidence that B[c]PH should be considered a potentially potent carcinogen in humans, and that rodent models may underestimate the risk.

An evaluation of the mutagenicity, metabolism, and DNA adduct formation of 5-nitrobenzo[b]naphtho[2,1-d]thiophene

Thioarenes, sulfur-containing polycyclic aromatic compounds, are environmental contaminants suspected of posing human health risks. In this study, 5-nitrobenzo[b]naphtho[2,1-d]thiophene (5-nitro-BNT), a nitrated-thioarene, was examined for its mutagenicity, metabolism and subsequent formation of DNA adducts. 5-Nitro-BNT was weakly mutagenic in Salmonella typhimurium strains TA98 and TA100 without Aroclor-1254-induced rat liver S9 (S9), and its activity was increased in the presence of S9. Anaerobic metabolism of 5-nitro-BNT by S9 or xanthine oxidase (XO) produced one major metabolite, identified as 5-amino-BNT by NMR, MS, and UV spectroscopy and by comparison with an authentic standard. Aerobic S9 metabolism of 5-nitro-BNT produced a major metabolite, identified as trans-9,10-dihydroxy-9,10-dihydro-5-nitro-BNT (5-nitro-BNT-9,10-diol). Also present was a minor amount of 5-amino-BNT and trans-9,10-dihydroxy-9,10-dihydro-5-amino-BNT (5-amino-BNT-9,10-diol). DNA adduct analyses were performed using the (32)P-postlabeling assay and reversed-phase HPLC. Three major XO-derived calf thymus DNA adducts were detected. On the basis of their chromatographic mobilities, two adducts were identified as reaction products of 5-nitro-BNT with 2'-deoxyguanosine and one adduct with 2'-deoxyadenosine. Incorporation of allopurinol (a specific XO inhibitor) in the incubation mixture resulted in loss of all three adducts, confirming enzymatic mediation by XO. Aerobic S9 activation of 5-nitro-BNT with calf thymus DNA produced three adducts. On the basis of their chromatographic mobilities, two were identified as reaction products of 5-nitro-BNT with 2'-deoxyguanosine and one with 2'-deoxyadenosine. Incorporation of 1-aminobenzotriazole (a P450 inhibitor) in the incubation mixture resulted in a loss of these adducts, confirming enzymatic mediation by P450. Aerobic S9-catalyzed metabolism of 5-nitro-BNT-9,10-diol produced the same DNA adducts as observed with 5-nitro-BNT. Aerobic S9-catalyzed metabolism of 5-amino-BNT-9,10-diol produced the same deoxyadenosine-derived DNA adducts as observed with 5-nitro-BNT and 5-nitro-BNT-9,10-diol. These results provide additional information that both ring oxidation and nitroreduction are involved in the metabolism, DNA adduct formation and mutagenicity of 5-nitro-BNT.

Influence of bulky polynuclear carcinogen lesions in a TATA promoter sequence on TATA binding protein-DNA complex formation

The TATA binding protein (TBP) is an essential component of the transcription initiation complex that recognizes and binds to the minor groove of the TATA DNA duplex consensus sequences. The objective of this study was to determine the effect of a carcinogen-modified adenine residue, positioned site-specifically within a regulatory TATA DNA sequence, on the binding of TBP. Two 25-mer oligonucleotides with stereoisomeric 10S (+)-trans-anti- or 10R (-)-trans-anti-BPDE-N(6)-dA residues at A(1) or A(2) within the TATA sequence element (5'-...TA(1)TAAA...-3')-(5'-...TTTA(2)TA...) were synthesized (anti-BPDE-N(6)-dA denotes an adduct formed from the reaction of r7,t8-dihydroxy-t9,10-epoxy-7,8,9,10-tetrahydobenzo[a]pyrene). The formation of complexes with TBP of these two sequences in the double-stranded forms (1 nM) were studied employing electrophoretic mobility shift assays (EMSA) at different TBP concentrations (0-70 nM). The overall affinity of TBP for the BPDE-modified target DNA sequences was weakly enhanced in the case of the (+)-trans or (-)-trans lesions positioned at site A(1) with K(d) approximately 8 and 6 nM, respectively (K(d) approximately 9 nM for the unmodified TATA DNA). Higher-order TBP-DNA complexes were observed at TBP concentrations in excess of approximately 15 nM. However, the stabilities of the biologically significant monomeric TBP-DNA complexes was dramatically increased or decreased, depending on the position of the lesion (A(1) or A(2)), or on its stereochemical and conformational characteristics. A molecular docking modeling approach was employed to insert the stereoisomeric BPDE residues into the known TATA box-TBP structure [Nikolov, D. B., et al. (1996) Proc. Natl. Acad. Sci. U.S.A. 4862-4867] to rationalize these observations. Native gel electrophoresis experiments with the same duplexes without TBP indicate that none of the modified sequences exhibit unusual bending induced by the lesions, nor that they differ from one another in this respect. These results suggest that the hydrophobic, bulky BPDE residues influence the binding of TBP by mechanisms other than prebending. The efficiency of RNA transcription of TBP-controlled promoters could be strongly influenced by the presence of such bulky lesions that could adversely affect the levels of gene expression.

Aggressive incidents in first-episode psychosis

BACKGROUND

Recent research has reported increased risk of aggressive incidents by individuals with psychotic illness.

AIMS

To examine acts of aggression in first-episode psychosis.

METHOD

Subjects with a first-episode psychosis were ascertained from a defined catchment area (Nottingham, UK) and reassessed at 3 years (n=166) using clinical interview, informants, health care and forensic records.

RESULTS

Of the subjects, 9.6% demonstrated at least one act of serious aggression (defined as weapon use, sexual assault or victim injury) during at least one psychotic episode and 23.5% demonstrated lesser acts of aggression (defined as all other acts of aggression). For all aggressive subjects (33.1%), unemployment (OR=3.6, 95% C11.6-8.0), comorbid substance misuse (OR=3.1, C1 1.1-8.8) and symptoms of overactivity at service contact (OR=6.9,C1 2.7-17.8) had independent effects on risk of aggression.

CONCLUSIONS

We confirmed some previously reported demographic and clinical associations with aggression in first-episode psychosis but no relationship with specific psychotic symptoms or diagnostic groups was observed.

Savings/credit group formation and change in contraception

We examine the characteristics of women who chose to join a women's savings or credit group organized by Save the Children USA in a rural area of Bangladesh, and the impact of participation on contraceptive use. The data are taken from a panel survey conducted in 1993, shortly before the groups were formed, and in 1995 after interventions began. Our findings show that although demographic and socioeconomic characteristics have only a weak relationship to the decision to join a program, the treatment that a woman receives from her husband is associated with participation. We also find evidence that the credit program tends to attract women who are already using contraception. The analysis of program impact on the use of modern contraceptives reveals a positive effect of the credit program, after we adjust for this selectivity; we see no evidence of an effect of participation in a savings group.

Bacteriophage T7 RNA polymerase transcription elongation is inhibited by site-specific, stereospecific benzo[c]phenanthrene diol epoxide DNA lesions

Benzo[c]phenanthrene diol epoxide (B[c]PhDE), the ultimate carcinogenic metabolite of the environmental pollutant benzo[c]phenanthrene, reacts with DNA primarily at the exocyclic amino groups of purines, forming B[c]PhDE-DNA adducts that differ in their stereochemical configurations and their effect on biological processes such as transcription. To determine the effect of these stereoisomers on RNA synthesis, in vitro T7 RNA polymerase transcription assays were performed using DNA templates modified on the transcribed strand by either a site-specific (+)-trans- or (-)-trans-anti-B[c]PhDE-N(6)-dA lesion located within the sequence 5'-CTCTCACTTCC-3'. The results show that both (-)-trans-anti-B[c]PhDE-N(6)-dA and (+)-trans-anti-B[c]PhDE-N(6)-dA block RNA synthesis. Furthermore, both B[c]PhDE-dA stereoisomeric adducts lead to lower levels of initiation of transcription relative to that observed using an unmodified DNA template. In contrast to these results, placement of the adduct on the nontranscribed strand within the template does not impede transcription elongation. In addition to the assessment of the effect of the lesions on transcription elongation, the resulting transcripts were characterized in terms of their base composition. A high level of base misincorporation is detected at the 3'-ends of truncated transcripts, with guanosine being most frequently incorporated opposite the modified nucleotide rather than the expected uridine. This result supports the notion that translocation past a modified base in a DNA template relies in part on correct base incorporation, and suggests that stalling of RNA polymerases at damaged sites in DNA may well be dependent on both the presence of the lesion and the base which is incorporated opposite the modified nucleotide.

Molecular topology of polycyclic aromatic carcinogens determines DNA adduct conformation: a link to tumorigenic activity

We report below on the solution structures of stereoisomeric "fjord" region trans-anti-benzo[c]phenanthrene-N2-guanine (designated (BPh)G) adducts positioned opposite cytosine within the (C-(BPh)G-C).(G-C-G) sequence context. We observe intercalation of the phenanthrenyl ring with stereoisomer-dependent directionality, without disruption of the modified (BPh)G.C base-pair. Intercalation occurs to the 5' side of the modified strand for the 1S stereoisomeric adduct and to the 3' side for the 1R stereoisomeric adduct, with the S and R-trans-isomers related to one another by inversion in a mirror plane at all four chiral carbon atoms on the benzylic ring. Intercalation of the fjord region BPh ring into the helix without disruption of the modified base-pair is achieved through buckling of the (BPh)G.C base-pair, displacement of the linkage bond from the plane of the (BPh)G base, adaptation of a chair pucker by the BPh benzylic ring and the propeller-like deviation from planarity of the BPh phenanthrenyl ring. It is noteworthy that intercalation without base-pair disruption occurs from the minor groove side for S and R-trans-anti BPh-N2-guanine adducts opposite C, in contrast to our previous demonstration of intercalation without modified base-pair disruption from the major groove side for S and R-trans-anti BPh-N6-adenine adducts opposite T. Further, these results on fjord region 1S and 1R-trans-anti (BPh)G adducts positioned opposite C are in striking contrast to earlier research with "bay" region benzo[a]pyrene-N2-guanine (designated (BP)G) adducts positioned opposite cytosine, where 10S and 10R-trans-anti stereoisomers were positioned with opposite directionality in the minor groove without modified base-pair disruption. They also are in contrast to the 10S and 10R-cis-anti stereoisomers of (BP)G adducts opposite C, where the pyrenyl ring is intercalated into the helix with directionality, but the modified base and its partner on the opposite strand are displaced out of the helix. These results are especially significant given the known greater tumorigenic potential of fjord region compared to bay region polycyclic aromatic hydrocarbons. The tumorigenic potential has been linked to repair efficiency such that bay region adducts can be readily repaired while their fjord region counterparts are refractory to repair. Our structural results propose a link between DNA adduct conformation and repair-dependent mutagenic activity, which could ultimately translate into structure-dependent differences in tumorigenic activities. We propose that the fjord region minor groove-linked BPh-N2-guanine and major groove-linked BPh-N6-adenine adducts are refractory to repair based on our observations that the phenanthrenyl ring intercalates into the helix without modified base-pair disruption. The helix is therefore minimally perturbed and the phenanthrenyl ring is not available for recognition by the repair machinery. By contrast, the bay region BP-N2-G adducts are susceptible to repair, since the repair machinery can recognize either the pyrenyl ring positioned in the minor groove for the trans-anti groove-aligned stereoisomers, or the disrupted modified base-pair for the cis-anti base-displaced intercalated stereoisomers.

Osteoporosis in men

Although less common than in women, osteoporosis in men is a prevalent worldwide problem with important socioeconomic implications. Our understanding of this condition in men is growing, but there remains a great deal more to be determined. Definitions for osteoporosis in men are needed. Cost-effective guidelines on who should be investigated and treated, and how, are clearly necessary. The role of bone mineral densitometry in diagnosis and treatment decisions needs to be clarified. The efficacy of drug therapies for osteoporosis in men requires greater attention. Currently, a large multicenter study is underway in the United States and should provide much needed insight into the epidemiology of osteoporosis in men.

Synthesis of (-)-[4-3H]epigallocatechin gallate and its metabolic fate in rats after intravenous administration

Because a great deal of attention has been focused on the metabolism of (-)-epigallocatechin gallate (EGCg), quantitative analysis of this compound is required. For this purpose we developed a method of chemical synthesis of [4-(3)H]EGCg. Synthesized [4-(3)H]EGCg showed 99.5% radiochemical purity and a specific activity of 13 Ci/mmol. To clarify the excretion route of EGCg, the radioactivity levels of bile and urine were quantified after intravenous administration of [4-(3)H]EGCg to bile-duct-cannulated rats. Results showed that the radioactivity of the bile sample excreted within 48 h accounted for 77.0% of the dose, whereas only 2.0% of the dose was recovered in the urine. The excretion ratio of bile to urine was calculated to be about 97:3. These results clearly showed that bile was the major excretion route of EGCg. Time-course analysis of the radioactivity in blood was also performed to estimate the pharmacokinetic parameters following intravenous administration of [4-(3)H]EGCg. In addition, EGCg metabolites excreted in the bile within 4 h after the intravenous dose of [4-(3)H]EGCg were analyzed by HPLC. The results showed that 4',4"-di-O-methyl-EGCg was present in the conjugated form and made up about 14.7% of the administered radioactivity.

Association of hypogonadism and estradiol levels with bone mineral density in elderly men from the Framingham study

BACKGROUND

Both hypogonadism and low estrogen levels adversely affect bone health in young men. In elderly men, who are at greatest risk for osteoporotic fracture, the influence of hypogonadism on bone mineral density remains unclear, as does the relative effect of estrogen status compared to hypogonadism.

OBJECTIVE

To examine the relation of hypogonadism and estrogen status to bone mineral density in elderly men.

DESIGN

Community-based, prospective cohort study.

SETTING

Framingham, Massachusetts.

PATIENTS

Male participants of the Framingham Study.

MEASUREMENTS

Total testosterone, total estradiol, and luteinizing hormone were measured in participants at all four biennial examinations from 1981 to 1989. Values from at least three of four examinations were averaged. Hypogonadism was defined as a mean testosterone level less than 10.4 nmol/L (<3.0 ng/mL) or a mean luteinizing hormone level of 20 IU/L or greater. An alternate definition of hypogonadism based only on a mean testosterone level less than 10.4 nmol/L (<3.0 ng/mL) was also used. In 1988-1989, bone mineral density was measured at the proximal femur (femoral neck, Ward triangle, and trochanter) and lumbar spine by using dual-photon absorptiometry and at the radial shaft by using single-photon absorptiometry. The association of hypogonadism with bone mineral density was examined with adjustment for confounders, including estradiol levels. A similar model that adjusted for hypogonadism was used to examine the association of estradiol level (ranked as quartiles) with bone mineral density.

RESULTS

Of 448 men with bone mineral density measurements, 405 had evaluable hormone levels (mean age, 75.7 years [range, 68 to 96 years]); 71 (17.5%) of the 405 men were hypogonadal. Bone mineral density at any site did not significantly differ in hypogonadal men compared with eugonadal men (for example, bone mineral density at the femoral neck was 0.89 g/cm(2) vs. 0.87 g/cm(2), respectively; P > 0.2), even when alternate definitions of hypogonadism were used. In contrast, compared with the lowest estradiol quartile, men with higher estradiol levels had greater mean bone mineral density at all sites (for example, bone mineral density at the femoral neck was 0.84 g/cm(2), 0.88 g/cm(2), 0.86 g/cm(2), and 0.91 g/cm(2) from the lowest to the highest estradiol quartile; P for trend = 0.002). The difference in mean bone mineral density between men in the lowest and those in the highest estradiol quartile levels was similar to the effect of 10 years of aging on bone mineral density.

CONCLUSIONS

In elderly men, hypogonadism related to aging has little influence on bone mineral density, but serum estradiol levels have a strong and positive association with bone mineral density.

Location of the epoxide function determines specificity of the allelic variants of human glutathione transferase Pi toward benzo[c]chrysene diol epoxide isomers

Carcinogenic activity of many polycyclic aromatic hydrocarbons (PAHs) is mainly attributed to their respective diol epoxides, which can be classified as either bay or fjord region depending upon the location of the epoxide function. The Pi class human glutathione (GSH) transferase (hGSTP1-1), which is polymorphic in humans with respect to amino acid residues in positions 104 (isoleucine or valine) and/or 113 (alanine or valine), plays an important role in the detoxification of PAH-diol epoxides. Here, we report that the location of the epoxide function determines specificity of allelic variants of hGSTP1-1 toward racemic anti-diol epoxide isomers of benzo[c]chrysene (B[c]C). The catalytic efficiency (k(cat)/K(m)) of V104,A113 (VA) and V104,V113 (VV) variants of hGSTP1-1 was approximately 2.3- and 1.7-fold higher, respectively, than that of the I104,A113 (IA) isoform toward bay region isomer (+/-)-anti-B[c]C-1,2-diol-3,4-epoxide. On the other hand, the IA variant was approximately 1.6- and 3.5-fold more efficient than VA and VV isoforms, respectively, in catalyzing the GSH conjugation of fjord region isomer (+/-)-anti-B[c]C-9,10-diol-11,12-epoxide. The results of the present study clearly indicate that the location of the epoxide function determines specificity of the allelic variants of hGSTP1-1 in the GSH conjugation of activated diol epoxide isomers of B[c]C.

Chemoprevention of lung tumorigenesis induced by a mixture of benzo(a)pyrene and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone by the organoselenium compound 1,4-phenylenebis(methylene)selenocyanate

We evaluated the chemopreventive efficacy of the organoselenium compound 1,4-phenylenebis(methylene)selenocyanate (p-XSC) against the development of tumors of the lung and forestomach induced by a mixture of benzo(a)pyrene (B(a)P) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), two of the major lung carcinogens present in tobacco smoke. A/J mice (20 mice/group) were given intragastric doses of a mixture of B(a)P (3 micromol/mouse) and NNK (3 micromol/mouse) in cottonseed oil (0.1 ml) once a week for eight consecutive weeks. Mice were fed either AIN-76A control diet or control diet containing p-XSC (10 ppm selenium), either during or after carcinogen administration. Dietary p-XSC significantly reduced lung tumor multiplicity, regardless of whether it was given during or after carcinogen administration. p-XSC was also an effective inhibitor of tumor development in the forestomach. To provide some biochemical insights into the protective role of p-XSC, its effect on selected phase I and II enzyme activities involved in the metabolism of NNK and B(a)P was also examined in vivo in this animal model. Dietary p-XSC significantly inhibited the activities of the phase I enzymes, methoxyresorufin O-dealkylase (MROD) and N-nitrosodimethylamine N-demethylase (NDMAD), in mouse liver, but it had no effect on ethoxyresorufin O-dealkylase (EROD), pentoxyresorufin O-dealkylase (PROD), and erythromycin N-demethylase (ERYTD). Total glutathione S-transferase (GST) enzyme activity, as well as GST-pi and GST-mu enzyme activities, were significantly induced by dietary p-XSC in both the lung and liver. Glutathione peroxidase (GPX) activity was also induced by p-XSC in mouse lung, but not in the liver. Dietary p-XSC had no effect on selenium-dependent glutathione peroxidase (GPX(Se)), GST-alpha, and UDP-glucuronosyl transferase (UDPGT) enzyme activities in either the lung or the liver. These studies suggest that the chemopreventive efficacy of p-XSC, when fed during carcinogen administration, may be, in part, due to the inhibition of certain phase I enzymes involved in the metabolic activation of these carcinogens, and the induction of specific phase II enzymes involved in their detoxification. The mechanisms that account for the effect of p-XSC when fed after carcinogen administration remain to be determined.

Studies on the synthesis of trans-dihydrodiols of polycyclic aromatic thiaarenes as potential proximate carcinogenic metabolites: first synthesis of trans-10,11-dihydroxy-10,11-dihydroacenaphtho[1, 2-b]benzo[d]thiophene and 6,7-dihydroxy-6,7-dihydronaphtho[1, 2-b]thiophene

Polyaromatic thiophene compounds are found to occur concomitantly with numerous coal-derived products and shale oils and are suspected mutagens and/or carcinogens. The first synthesis of the two title compounds 9 and 16 has been achieved in five or four steps starting from 8,9-dihydroacenaphtho[1,2-b]benzo[d]thiophene (1) and 7-methoxynaphtho[1,2-b]thiophene (12), respectively. Compound 1 was converted to the cis-diol (11) (via treatment with OsO(4)/pyridine) or to trans-diol (3) [via Prevost reaction (PhCOOAg/I(2)) followed by hydrolysis] in 95-98% yield, respectively. Subsequent dehydration (PTS/benzene) of the diol followed by aromatization of the resulting ketone (5) produced the phenolic compound 6 in 97% yield. Oxidation of the phenol with phenyl iododiacetate followed by hydrolysis of the o-quinone monoketal 7 gave the o-quinone (8) in 86% yield. Stereoselective reduction of 8 with NaBH(4)/EtOH under oxygen afforded trans-10,11-dihydroxy-10,11-dihydroacenaphtho[1,2-b]benzo[d]thi oph ene(9) (orange yellow solid) in 55% yield. Compound 16 was obtained as a colorless solid, through the stereoselective reduction of the o-quinone 15 (with NaBH(4)), which in turn was prepared from 12 following the protocol of functional group transformation of methoxy --> phenol --> o-quinone monoketal --> o-quinone, as used in the previous case. The yields for all the steps are very good. The mutagenicity assay of compound 9 and 16 as well as their parent thiaarenes have been performed. The results showed that 9 may not be the proximate carcinogen of acenaphtho[1,2-b]benzo[d]thiophene, while it is likely that compound 16 is one of the possible proximate carcinogens for naphtho[1,2-b]thiophene.

Coexposure to ethanol with N-nitrosodimethylamine or 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone during lactation of rats: marked increase in O(6)-methylguanine-DNA adducts in maternal mammary gland and in suckling lung and kidney

Use of alcoholic beverages increases risk of cancer at several target sites, including the breast. Of several possible mechanisms for this effect, competitive inhibition by ethanol of hepatic clearance of nitrosamines, resulting in increased dose delivery to posthepatic tissues, gives the quantitatively most pronounced enhancement. We investigated whether this effect would pertain to the mammary gland, and to ethanol and nitrosamines delivered translactationally to sucklings. Ethanol (1.6 g/kg) was administered by gavage to nursing Sprague-Dawley rats 10 min before 5 mg/kg N-nitrosodimethylamine (NDMA) or 50 mg/kg 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK); treatment was on postnatal days 1, 7, or 14. Tissues taken 4 h later for analysis of O(6)-methylguanine in DNA were liver, blood, and mammary glands from the mothers, and liver, lung, kidney, and blood from the sucklings. Ethanol cotreatment resulted in a marked, 10-fold increase in O(6)-methylguanine adducts from NDMA in mammary gland, as well as smaller but significant increases in this tissue from NNK and in maternal blood cells from both chemicals; adducts in maternal liver decreased slightly. In the sucklings, ethanol cotreatment also lowered adducts in liver after NDMA or NNK treatment. After NDMA, adducts were also detected in suckling lung and kidney and were increased five- to 10-fold after ethanol coexposure. Adducts from either chemical, with or without ethanol, decreased markedly in all suckling tissues with development from postnatal day 1 to day 14. Thus ethanol coexposure with nitrosamines increases O(6)-methylguanine DNA adducts in mammary gland and strongly influences adduct formation in suckling tissues after translactational delivery.

Quantitative reactions of anti 5,9-dimethylchrysene dihydrodiol epoxide with DNA and deoxyribonucleotides

Native as well as denatured calf thymus DNA, deoxyguanylic and deoxyadenylic acid, respectively, were reacted with the racemic anti 5,9-dimethylchrysene dihydrodiol epoxide (5,9-DMCDE). The deoxyribonucleoside adducts were separated by HPLC and characterized by CD and NMR. Approximately 17% of the epoxide was trapped by native DNA and 76% of the adducts were derived from the RSSR enantiomer. The ratios of dAdo/dGuo modification in DNA were 14/86 and 19/81 for RSSR and SRRS enantiomers, respectively. By monitoring the product yields of anti 5,9-DMCDE with DNA and deoxyribonucleotides, we hoped to gain further insight into the factors responsible for deoxyguanosine adduct formation by 5-methylchrysene dihydrodiol epoxide (5-MCDE) compared to 5, 6-dimethylchrysene dihydrodiol epoxide (5,6-DMCDE). The adduct yields in deoxyribonucleotide reactions of 5,9-DMCDE were slightly higher than those from 5-MCDE. However, the reaction yields of 5, 9-DMCDE with DNA were lower than those with 5-MCDE in most cases, particularly for the cis and trans deoxyadenosine adducts. It seems that the 9-methyl group of 5,9-DMCDE significantly influences adduct formation with the deoxyadenosine residue in DNA in contrast to the 6-methyl group of 5,6-DMCDE. The 9-methyl group sterically decreases deoxyadenosine adduct yields more in reaction with native DNA than denatured DNA, but it has little effect on deoxyribonucleotide reactions. Adduct formation with deoxyguanosine residues in DNA by all three dihydrodiol epoxides correlate with their respective tumorigenic and mutagenic activities.

Synthesis of anti-1,2-dihydroxy-3,4-epoxy-1,2,3, 4-tetrahydro-6-nitrochrysene and its reaction with 2'-deoxyguanosine- 5'-monophosphate, 2'-deoxyadenosine-5'-monophosphate, and calf thymus DNA in vitro

The remarkable carcinogenic activity of 6-nitrochrysene (6-NC) in several animal models, and its environmental presence, suggest its potential importance with regard to human cancer development. Depending on the bioassay model, 6-NC can be activated by simple nitro reduction, ring oxidation, or by a combination of ring oxidation and nitro reduction. Only the first pathway has been clearly established. Thus, this study purports to unequivocally define the other pathways. Toward this end, we report for the first time the synthesis of anti-1,2-dihydroxy-3,4-epoxy-1,2,3, 4-tetrahydro-6-nitrochrysene (6-NCDE), a likely ultimate carcinogenic metabolite of 6-NC. Also, we describe our initial investigation of its binding with calf thymus DNA, 2'-deoxyguanosine-5'-monophosphate (2'-dGuo), and 2'-deoxyadenosine-5'-monophosphate (2'-dAdo) in vitro. These adduct markers were then employed for comparison with those obtained in the rat after in vivo treatment with 6-NC. On the basis of the results, it appears that the major adduct formed in the liver of rats treated with 6-NC is not derived from 6-NCDE.

Accomodation of S-cis-tamoxifen-N(2)-guanine adduct within a bent and widened DNA minor groove

The non-steroidal anti-estrogen tamoxifen [TAM] has been in clinical use over the last two decades as a potent adjunct chemotherapeutic agent for treatment of breast cancer. It has also been given prophylactically to women with a strong family history of breast cancer. However, tamoxifen treatment has also been associated with increased endometrial cancer, possibly resulting from the reaction of metabolically activated tamoxifen derivatives with cellular DNA. Such DNA adducts can be mutagenic and the activities of isomeric adducts may be conformation-dependent. We therefore investigated the high resolution NMR solution conformation of one covalent adduct (cis-isomer, S-epimer of [TAM]G) formed from the reaction of tamoxifen [TAM] to N(2)-of guanine in the d(C-[TAM]G-C).d(G-C-G) sequence context at the 11-mer oligonucleotide duplex level. Our NMR results establish that the S-cis [TAM]G lesion is accomodated within a widened minor groove without disruption of the Watson-Crick [TAM]G. C and flanking Watson-Crick G.C base-pairs. The helix axis of the bound DNA oligomer is bent by about 30 degrees and is directed away from the minor groove adduct site. The presence of such a bulky [TAM]G adduct with components of the TAM residue on both the 5'- and the 3'-side of the modified base could compromise the fidelity of the minor groove polymerase scanning machinery.

Gestational and lactational exposure to TCDD or coplanar PCBs alters adult expression of saccharin preference behavior in female rats

Previous studies have shown that maternal doses of 1 microg/kg or less of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in late gestation can demasculinize and feminize reproductive behavior in male rats. However, it was not known whether coplanar polychlorinated biphenyls (PCBs) had similar effects, or whether non-reproductive sexually dimorphic behaviors such as saccharin preference behavior were also altered. We determined the effects of TCDD or coplanar PCBs on saccharin consumption and saccharin preference in male and female rats. Sprague-Dawley rats were dosed with 3,3',4, 4'-tetrachlorobiphenyl (PCB 77; 2 or 8 mg/kg/day), 3,3',4,4', 5-pentachlorobiphenyl (PCB 126; 0.25 or 1.0 microg/kg/day), TCDD (0. 025 or 0.10 microg/kg/day), or corn oil vehicle on days 10-16 of gestation. Maternal exposure to TCDD or coplanar PCBs did not change saccharin consumption or saccharin preference in male rats. However, TCDD and coplanar PCB-exposed females showed decreased saccharin consumption and saccharin preference. The results indicate that saccharin consumption is masculinized in female rats exposed to TCDD or coplanar PCBs during perinatal development. This effect could be related to the anti-estrogenic actions of these chemicals.

Vaccine-induced apoptosis: a novel clinical trial end point?

The functional end point of immunotherapy is to induce tumor regression. Because immune effector mechanisms usually result in apoptosis, the aim of this study was to determine whether measurement of tumor apoptosis ex vivo is a good end point to evaluate the efficacy of cancer vaccines. A prototype vaccine, 105AD7, was administered to colorectal cancer patients before resection of their primary tumors. There was a significant increase in apoptosis of tumor cells within immunized patients compared with control patients as assessed by immunohistochemistry (P = 0.005; n = 16) or by flow cytometry (P = 0.003; n = 34). Preoperative immunization and measurement of tumor cell apoptosis may be a valuable clinical end point for evaluation of new vaccine and other biological approaches.

The BCSH guideline on addressograph labels: experience at a cardiothoracic unit and findings of a telephone survey

In 1998 we implemented a BCSH recommendation that addressograph labels should not be used on blood transfusion specimen tubes. Over a 12-month period before the ban was introduced our laboratory received 5964 red cell transfusion requests, 182 (3.1%) of which contained an error in the identification details (ID) supplied on the request form and/or specimen. Three of these errors were of the 'wrong patient' type, i.e. the sample belonged to a different patient from the one whose ID appeared on the specimen tube and request form. Over the 12 months after the ban was introduced 511 (8. 1%) of 6326 requests contained a labelling error, an increase in error rate of 165%; no wrong-patient errors were identified, however. In a survey, seven (29.2%) of 24 transfusion laboratories in the UK accepted specimens labelled with addressograph stickers; in four of these cases a local blood transfusion committee had agreed that the BCSH guideline should not be followed. We believe the BCSH guideline is valid; its implementation, however, has major financial and workload implications, which probably explains why many hospitals apparently do not comply with it.

Modulation of growth of human prostate cancer cells by the N-acetylcysteine conjugate of phenethyl isothiocyanate

There is growing evidence that thiol conjugates of isothiocyanates present in cruciferous vegetables are effective cancer chemopreventive and potentially active therapeutic agents. The effects of the N-acetylcysteine conjugate of phenethyl isothiocyanate (PEITC-NAC) on tumor cell growth were analyzed in human prostate cancer cell lines LNCaP, androgen-dependent, and DU-145, androgen-independent. Exposure of the cells to PEITC-NAC at high concentrations caused cytolysis, while at lower concentrations PEITC-NAC mediated a dose-dependent growth modulation, with reduction of DNA synthesis and growth rate, inhibition of clonogenicity and induction of apoptosis in both types of prostate cancer cells. PEITC-NAC decreased cells in S and G2M phases of cell cycle, blocking cells entering replicating phases. In parallel, a significant enhancement of cells expressing the cell cycle regulator p21 as well as its intensity was determined using a fluorescent antibody technique. The action of PEITC-NAC was time-dependent, with the magnitude of inhibition increasing to 50-65% after PEITC-NAC exposure for several days. Interaction of tumor cells with dissociation products of PEITC-NAC, PEITC and NAC, are proposed as the mechanism of growth regulation.

Targeting of lung cancer mutational hotspots by polycyclic aromatic hydrocarbons

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in combustion products of organic matter, including cigarette smoke. Metabolically activated diol epoxides of these compounds, including benzo[a]pyrene diol epoxide (B[a]PDE), have been suggested as causative agents in the development of lung cancer. We previously mapped the distribution of B[a]PDE adducts within the p53 tumor suppressor gene (also known as TP53), which is mutated in 60% of human lung cancers, and found that B[a]PDE adducts preferentially form at lung cancer mutational hotspots (codons 154, 157, 158, 245, 248, and 273). Other PAHs may be important in lung cancer as well.

METHODS

Here we have mapped the distribution of adducts induced by diol epoxides of additional PAHs: chrysene (CDE), 5-methylchrysene (5-MCDE), 6-methylchrysene (6-MCDE), benzo[c]phenanthrene (B[c]PDE), and benzo[g]chrysene (B[g]CDE) within exons 5, 7, and 8 of the p53 gene in human bronchial epithelial cells.

RESULTS

CDE exposure produced only low levels of adducts. Exposure of cells to the other activated PAHs resulted in DNA damage patterns similar to those previously observed with B[a]PDE but with some distinct differences. 5-MCDE, 6-MCDE, B[g]CDE, and B[c]PDE efficiently induced adducts at guanines within codons 154, 156, 157, 158, and 159 of exon 5, codons 237, 245 and 248 of exon 7, and codon 273 of exon 8, but the relative levels of adducts at each site varied for each compound. B[g]CDE, B[c]PDE, and 5-MCDE induced damage at codon 158 more selectively than 6-MCDE or B[a]PDE. The sites most strongly involved in PAH adduct formation were also the sites of highest mutation frequency (codons 157, 158, 245, 248, and 273).

CONCLUSION

The data suggest that PAHs contribute to the mutational spectrum in human lung cancer.

The effects of 1-nitropyrene, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine and 7,12-dimethylbenz[a]anthracene on 8-hydroxy-2'-deoxyguanosine levels in the rat mammary gland and modulation by dietary 1,4-phenylenebis(methylene) selenocyanate

Humans are exposed to 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 1-nitropyrene (1-NP) via several environmental sources and both are known mammary carcinogens in rodents, with the former being more potent (K. El-Bayoumy, Y.-H. Chae, P. Upadhyaya, A. Rivenson, K. Kurtzke, B. Reddy, S.S. Hecht, Comparative tumorigenicity of benzo[a]pyrene, 1-nitropyrene, and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine administered by gavage to female CD rats, Carcinogenesis 16 (1995) 431-434). Following their metabolic activation, both carcinogens are known to bind covalently to DNA. However, it remains to be determined whether these carcinogens can also induce DNA-base oxidation. Our goal was to determine the effects of PhIP and 1-NP on the levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG; a marker of oxidative DNA damage) in rat mammary glands and to evaluate the effect of the chemopreventive agent 1,4-phenylenebis(-methylene)selenocyanate (p-XSC) as an inhibitor of such damage. As an established potent mammary carcinogen, the synthetic 7,12-dimethylbenz[a]anthracene (DMBA) was included in this study. Female CD rats were fed a high-fat AIN-76A diet (23.5% corn oil) supplemented with p-XSC (10 ppm as selenium) or unsupplemented control diet for 1 week. At 50 days of age, each rat (12 rats/group) was gavaged with either PhIP (22 mg (100 micromol) per rat) or I-NP (20 mg (80 micromol) per rat) in trioctanoin (0.5 ml), DMBA (5 mg (20 micromol) per rat] in olive oil (0.2 ml), or the corresponding vehicle. Rats were sacrificed 6 and 24 h after carcinogen treatment (six rats per time point). Mammary fat pads were excised and DNA was isolated and enzymatically hydrolyzed. The hydrolysates were analyzed for 8-OHdG using HPLC with EC detection. PhIP significantly increased the levels of 8-OHdG by 83% after 6 h (P < 0.05), but the increase (47%) at the 24 h point was not significant. p-XSC alone had no effect on the levels of 8-OHdG. However, the elevation of 8-OHdG caused by PhIP at 6 h was significantly inhibited by p-XSC to levels similar to those measured in rats treated with the vehicle only (P < 0.05). p-XSC had no effect on PhIP-induced 8-OHdG at 24 h. I -NP had no effect on the levels of 8-OHdG at either time point. Levels of 8-OHdG were increased by 22% 6 h after DMBA administration and, significantly, rose to 84% at 24 h (P < 0.01); at either time point, this elevation was not inhibited by p-XSC. Although the mechanisms remain to be determined, to our knowledge, this is the first report demonstrating that PhIP and DMBA are capable of enhancing 8-OHdG levels in the rat mammary tissue in vivo.

Unrepaired fjord region polycyclic aromatic hydrocarbon-DNA adducts in ras codon 61 mutational hot spots

The fjord region diol-epoxide metabolites of polycyclic aromatic hydrocarbons display stronger tumorigenic activities in rodent studies than comparable bay region diol-epoxides, but the molecular basis for this difference between fjord and bay region derivatives is not understood. Here we tested whether the variable effects of these genotoxic metabolites of polycyclic aromatic hydrocarbons may result from different DNA repair reactions. In particular, we compared the repairability of DNA adducts formed by bay region benzo[a]pyrene (B[a]P) diol-epoxides and the structurally similar but significantly more tumorigenic fjord region diol-epoxide metabolites of benzo[c]phenanthrene (B[c]Ph). For that purpose, we incorporated both types of polycyclic aromatic hydrocarbon adducts into known hot spot sites for carcinogen-induced proto-oncogene activation. Synthetic DNA substrates were assembled using a portion of human N-ras or H-ras that includes codon 61, and stereospecific B[a]P or B[c]Ph adducts were synthesized on adenine N6 at the second position of these two ras codon 61 sequences. DNA repair was determined by incubating the site-directed substrates in human cell extracts, followed by electrophoretic visualization of radiolabeled oligonucleotide excision products. These cell-free assays showed that all tested bay region B[a]P-N6-dA adducts are removed by the human nucleotide excision repair system, although excision efficiency varied with the particular stereochemical configuration of each B[a]P residue. In contrast, all fjord region B[c]Ph-N6-dA adducts located in the identical sequence context and with exactly the same stereochemical properties as the corresponding B[a]P lesions were refractory to the nucleotide excision repair process. These findings indicate that the exceptional tumorigenic potency of B[c]Ph or related fjord region diol-epoxides may be attributed, at least in part, to slow repair of the stable base adducts deriving from the reaction of these compounds with DNA.

Analgesic principle from Abutilon indicum

Bioactivity guided isolation of Abutilon indicum yielded eugenol [4-allyl-2-methoxyphenol], which was found to possess significant analgesic activity. At doses of 10, 30, and 50 mg/kg body weight, eugenol exhibited 21.30 (p < 0.05), 42.25 (p < 0.01) and 92.96% (p < 0.001) inhibition of acetic acid induced writhing in mice. At a dose of 50 mg/kg body weight, eugenol showed 33.40% (p < 0.05) prolongation of tail flicking time determined by the radiant heat method.

Three-year outcome of first-episode psychoses in an established community psychiatric service

BACKGROUND

Changes in service provision, secular trends in substance misuse and changing social structures might affect outcome in psychosis.

AIMS

To assess the three-year outcome of an inception cohort of first-episode psychoses treated in a modern, community-oriented service; to compare outcomes with an earlier cohort treated in hospital-based care; and to examine the predictive validity of ICD-10 diagnostic criteria.

METHOD

Three-year follow-up (1995-1997) of an inception cohort of first-episode psychoses and comparison with two-year follow-up (1980-1982) of the Determinants of Outcome of Severe Mental Disorders (DOSMED) Nottingham cohort.

RESULTS

On most outcome measures, non-affective psychoses had a worse outcome than affective psychoses. Affective psychoses had better outcome than previously reported. Substance-related psychoses had very poor occupational outcome. Similar proportions of the current and DOSMED cohort were in remission but the former were rated as having greater disability.

CONCLUSIONS

In a modern community service, 30-60% of patients with first-episode psychoses experience a good three-year outcome. The ICD-10 criteria have good predictive validity.

A neoadjuvant clinical trial in colorectal cancer patients of the human anti-idiotypic antibody 105AD7, which mimics CD55

Thirty-five patients received 105AD7 human anti-idiotype vaccination prior to surgery for colorectal carcinoma. Patients were immunized before and also received one to two immunizations after surgical resection of their colorectal cancer. The vaccine was well tolerated with no associated toxicity. Lymphocytic infiltration within the resected tumors was quantified by immunohistochemistry and image analysis. Enhanced infiltration of helper T cells (CD4) and natural killer (NK) cells (CD56) were observed in the tumors from immunized patients when compared with tumors from stage, grade, site, age, and sex matched unimmunized patients. NK activity was increased in the blood, peaking 7-10 days post immunization and then dropping rapidly and correlating with NK extravasation within the tumor. Comparison of the amino acid sequences of 105AD7 anti-idiotype and the antigen it mimics, CD55, has predicted that patients with HLA-DR1, HLA-DR3, and HLA-DR7 haplotypes should show helper T cell responses following 105AD7 vaccination. Eighty-three percent of patients expressing these haplotypes responded to 105AD7, whereas 88% of patients who failed to express these haplotypes were nonresponders. With a median follow-up of 4 years (range, 2.5-6 years) 65% of patients remained disease free. This trial shows that 105AD7 stimulates antitumor inflammatory responses allowing extravasation within tumor deposits of both helper T cells and NK cells. This represents a way of evaluating immune responses in patients both within the blood and at the tumor site. The study confirms that immunization with a human anti-idiotypic antibody results in immune responses in 83% of patients with a permissive haplotype.

Diagnostic stability of first-episode psychosis. Comparison of ICD-10 and DSM-III-R systems

BACKGROUND

The temporal stability of a diagnosis is one measure of its predictive validity.

AIMS

To measure diagnostic stability in first-episode psychosis using ICD-10 and DSM-III-R.

METHOD

Between 1992 and 1994 we ascertained a cohort of persons with first-episode psychosis (n = 168), assigning to each a consensus diagnosis. At three-year follow-up, longitudinal consensus diagnoses, blind to onset diagnoses, were made. Stability was measured by the positive predictive values (PPVs) of onset diagnoses. For onset schizophrenia, we also calculated sensitivity, specificity and concordance (kappa).

RESULTS

First-episode ICD-10 and DSM-III-R schizophrenia had a PPV of over 80% at three years. Over one-third of cases with ICD-10 F20 schizophrenia at three years had non-schizophrenia diagnoses at onset. Manic psychoses showed the highest PPV (91%). For onset schizophrenia, both systems had high specificity (ICD-10: 89; DSM-III-R: 93%), but low sensitivity (ICD-10: 64%; DSM-III-R: 51%) and moderate concordance (ICD-10: 0.54; DSM-III-R: 0.46).

CONCLUSIONS

Bipolar disorders and schizophrenia showed the highest stability. DSM-III-R schizophrenia did not have greater stability than ICD-10 schizophrenia.

Fibrin glue reduces the severity of intra-abdominal adhesions in a rat model

BACKGROUND

The purpose of this study was to determine whether fibrin glue inhibits intra-abdominal adhesions.

METHODS

Twenty rats underwent midline laparotomy. To maximize adhesions, bilateral peritoneal muscular defects were created and covered with polypropylene mesh sewn with a braided suture. The bowel was abraded with dry gauze. Rats were randomized to either fibrin glue (FG) sprayed over the mesh or to control (no further treatment) groups. At 1 week, the adhesion density (graded 0 to 3), the percentage of the patch covered by adhesion (0% to 100%), and adhesion type were recorded.

RESULTS

The mean adhesion density was 1.45+/-0.33 for FG versus 2.8+/-0.11 for controls (P = 0.001). The mean percentage of adhesions was 36+/-9.9 for the FG group and 94+/-3.7 for controls (P = 0.0002). Bowel or solid organs were adherent to the patch in 6 of 20 (30%) in the FG group versus 12 of 20 (70%) in controls (P = 0.057).

CONCLUSIONS

Topical fibrin glue reduces the density and severity of intra-abdominal adhesions in a rat model.

Metabolic fate of glutathione conjugate of benzo[a]pyrene-(7R,8S)-diol (9S,10R)-epoxide in human liver

Benzo[a]pyrene-(7R,8S)-diol (9S,10R)-epoxide [(+)-anti-BPDE] is believed to be the activated form of the widely spread environmental pollutant benzo[a]pyrene. Glutathione (GSH) S-transferase (GST)-catalyzed conjugation of (+)-anti-BPDE with GSH is an important mechanism in its cellular detoxification. Here, we report that the GSH conjugate of (+)-anti-BPDE [(-)-anti-BPD-SG] is a potent inhibitor (K(i) 15 microM) of class Mu human GST isoenzyme, which, among human liver GSTs, is a highly efficient detoxifier of (+)-anti-BPDE. Thus, the inhibition of GST activity by (-)-anti-BPD-SG may hinder GSH conjugation of (+)-anti-BPDE, unless the conjugate is metabolized and/or eliminated. The results of the present study show that gamma-glutamyltranspeptidase (gamma-GT) can metabolize (-)-anti-BPD-SG at a rate of about 0.29 nmol/min/mg protein. Our studies also show that (-)-anti-BPD-SG is transported across the human canalicular liver plasma membrane (cLPM) in an ATP-dependent manner at a rate of about 0.33 nmol/min/mg protein. The ATP-dependent transport of (-)-anti-[(3)H]BPD-SG across human cLPM follows Michaelis-Menten kinetics (K(m) 84 microM; V(max) 0.33 nmol/min/mg). In conclusion, the results of the present study suggest that both gamma-GT-mediated metabolism and ATP-dependent canalicular transport may be important steps in overall detoxification of (+)-anti-BPDE in the human liver.

Chemoprevention of carcinogen-induced mammary tumorigenesis by the hybrid polar cytodifferentiation agent, suberanilohydroxamic acid (SAHA)

Hybrid Polar Cytodifferentiation (HPC) agents represent a novel class of anticancer compounds which act by inducing terminal differentiation and/or apoptosis rather than by cytotoxic action. Among these are HPC agents such as hexamethylenebisacetamide (HMBA) and more potent 2nd generation hybrid/polar compounds such as suberanilohydroxamic acid (SAHA). As of the present, most studies on HPC agents have focused on cancers of the hematopoietic system rather than solid epithelial tumors. The objective of the present study therefore was to assess the chemopreventive action of these two related compounds in the N-methylnitrosourea (NMU)-induced rat mammary tumor model. Female Sprague-Dawley rats were fed diets containing 450 and 900 ppm, SAHA and 1000 and 2000 ppm HMBA, starting one week prior to NMU administration and continued for a period of 18 weeks. Mammary tumor development was monitored by palpation throughout the study, and at termination tumor incidence, number, multiplicity, latency and volume were determined. Weight gain was measured biweekly throughout the study. The salient results were as follows: SAHA at 900 ppm reduced NMU-induced mammary tumor incidence by 40%, total tumors by 66%, mean tumor multiplicity by 43% and mean tumor volume by 78%, with no detectable toxic side effects. HMBA exerted no tumor inhibiting effects at either concentration. This study represents the first demonstration that an HPC agent, namely SAHA, can inhibit the development of a chemically-induced, solid, epithelial tumor, at a relatively low dose (approximately 13 mgs/rat/day) without untoward side effects.

A quantitative comparison of dibenzo[a,l]pyrene-DNA adduct formation by recombinant human cytochrome P450 microsomes

Dibenzo[a,l]pyrene (DB[a,l]P), an extremely potent environmental carcinogen, is metabolically activated in mammalian cells and microsomes through the fjord-region dihydrodiol, trans-DB[a,l]P-11, 12-diol, to syn- and anti-DB[a,l]P-11,12-diol-13,14-epoxides (syn- and anti-DB[a,l]PDEs). The role of seven individual recombinant human cytochrome P450s (1A1, 1A2, 1B1, 2B6, 2C9, 2E1, and 3A4) in the metabolic activation of DB[a,l]P and formation of DNA adducts was examined by using (32)P postlabeling, thin-layer chromatography, and high-pressure liquid chromatography. We found that, in the presence of epoxide hydrolase, only P450 1A1 and P450 1B1 catalyzed the formation of DB[a,l]PDE-DNA adducts and several unidentified polar adducts. Human P450 1A1 catalyzed the formation of DB[a, l]PDE-DNA adducts and unidentified polar adducts at rates threefold and 17-fold greater than did human P450 1B1 (256 fmol/h/nmol P450 versus 90 fmol/h/nmol P450 and 132 fmol/h/nmol P450 versus 8 fmol/h/nmol P450, respectively). P450 1A1 DNA adducts were derived from both anti- and syn-DB[a,l]PDE at rates of 73 fmol/h/nmol P450 and 51 fmol/h/nmol P450, respectively. P450 1B1 produced adducts derived from anti-DB[a,l]PDE at a rate of 82 fmol/h/nmol, whereas only a small number of adducts were derived from syn-DB[a,l]PDE (0.4 fmol/h/nmol). These results demonstrated the potential of human P450 1A1 and P450 1B1 to contribute to the metabolic activation and carcinogenicity of DB[a,l]P and provided additional evidence that human P450 1A1 and 1B1 differ in their stereospecific activation of DB[a,l]P. Mol. Carcinog. 26:74-82, 1999. Published 1999 Wiley-Liss, Inc.

Solution conformation of the (+)-trans-anti-benzo[g]chrysene-dA adduct opposite dT in a DNA duplex

The solution structure of the adduct derived from the covalent bonding of the fjord region (+)-(11S, 12R, 13R, 14S) stereoisomer of anti -11,12-dihydroxy-13,14-epoxy-11,12,13, 14-tetrahydrobenzo[g]chrysene, (+)- anti -B[g]CDE, to the exocyclic N(6)amino group of the adenine residue dA6, (designated (+)- trans-anti -(B[g]C)dA6), positioned opposite a thymine residue dT17 in the DNA sequence context d(C1-T2-C3-T4-C5-(B[g]C)A6-C7-T8-T9-C10-C11). d(G12-G13-A14-A15-G16-T17-G18-A19-G20++ +-A21-G22) (designated (B[g]C)dA. dT 11-mer duplex), has been studied using structural information derived from NMR data in combination with molecular dynamics (MD) calculations. The solution structure of the (+)- trans-anti -(B[g]C)dA.dT 11-mer duplex has been determined using an MD protocol where both interproton distance and dihedral angle restraints deduced from NOESY and COSY spectra are used during the refinement process, followed by additional relaxation matrix refinement to the observed NOESY intensities to account for spin diffusion effects. The results established that the covalently attached benzo[g]chrysene ring intercalates into the DNA helix directed towards the 5'-side of the modified strand and stacks predominantly with dT17 when intercalated between dC5.dG18 and (B[g]C)dA6.dT17 base-pairs. All base-pairs, including the modified (B[g]C)dA6.dT17 base-pair, are aligned through Watson-Crick pairing as in normal B -DNA. In addition, the potential strain associated with the highly sterically hindered fjord region of the aromatic portion of the benzo[g]chrysenyl ring is relieved through the adoption of a non-planar, propeller-like geometry within the chrysenyl ring system. This conformation shares common structural features with the related (+)- trans-anti -(B[c]Ph)dA adduct in the identical base sequence context, derived from the fjord region (+)-(1S,2R,3R,4S)-3, 4-dihydroxy-1,2-epoxy-1,2,3,4-tetrahydrobenzo[c]phenanthrene stereoisomer, in which intercalation is also observed towards the 5'-side of the modified dA6.dT17 base-pair.

Primer length dependence of binding of DNA polymerase I Klenow fragment to template-primer complexes containing site-specific bulky lesions

The binding of the benzo[a]pyrene metabolite anti-BPDE (r7, t8-dihydroxy-t9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene) to the N(2) group of 2'-deoxyguanosine residues (dG) is known to adversely affect the Michaelis-Menten primer extension kinetics catalyzed by DNA Pol I and other polymerases. In this work, the impact of site-specific, anti-BPDE-modified DNA template strands on the formation of Pol I (Klenow fragment, KF)/template-primer complexes has been investigated. The 23-mer template strand 5'-d(AAC GC-(1) T(-)(2) ACC ATC CGA ATT CGC CC), I (dG = (+)-trans- and (-)-trans-anti-BPDE-N(2)-dG), was annealed with primer strands 18, 19, or 20 bases long. Complex formation of these template-primer strands with KF(-) (exonuclease-free) at different enzyme concentrations was determined using polyacrylamide gel mobility shift assays in the absence of dNTPs. The lesion dG causes an increase in the dissociation constants, K(d), of the monomeric, 1:1 KF(-)/DNA template-primer complexes by factors of 10-15 when the 3'-end base of the primer strand is positioned either opposite dG, or opposite dC(-)(1) in I, and the shapes of the binding isotherms are sigmoidal. The sigmoidal shapes are attributed to the formation of dimeric 2:1 KF(-)/DNA template-primer complexes. In contrast, when the 3'-end of the primer strand extends only to dT(-)(2) in I, the K(d) of 1:1 complexes is increased by factors of only 2-3, the shapes of the binding isotherms are hyperbolic and nonsigmoidal and are similar to those observed with the unmodified control, and monomeric KF(-)/DNA complexes are dominant. The impact of bulky lesions on polymerase/DNA complex formation in polymerase-catalyzed primer extension reactions needs to be taken into account in interpreting the site-specific Michaelis-Menten kinetics of these reactions.

Solution structure of the (+)-cis-anti-benzo[a]pyrene-dA ([BP]dA) adduct opposite dT in a DNA duplex

Minor adducts, derived from the covalent binding of anti-benzo[a]pyrene-7,8-dihydroxy-9,10-epoxide to cellular DNA, may play an important role in generating mutations and initiating cancer. We have applied a combined NMR-computational approach including intensity based refinement to determine the solution structure of the minor (+)-cis-anti-[BP]dA adduct positioned opposite dT in the d(C1-T2-C3-T4-C5-[BP]A6-C7-T8-T9-C10-C11). (d(G12-G13-A14-A15-G16-T17-G18-A19-G20+ ++-A21-G22) 11-mer duplex. The BP ring system is intercalated toward the 5'-side of the [BP]dA6 lesion site without disrupting the flanking Watson-Crick dC5.dG18 and [BP]dA6.dT17 base pairs. This structure of the (+)-cis-anti-[BP]dA.dT 11-mer duplex, containing a bay region benzo[a]pyrenyl [BP]dA adduct, is compared with the corresponding structure of the (+)-trans-anti-[BPh]dA.dT 11-mer duplex (Cosman et al., Biochemistry 32, 12488-12497, 1993), which contains a fjord region benzo[c]phenanthrenyl [BPh]dA adduct with the same R stereochemistry at the linkage site. The carcinogen intercalates toward the 5'-direction of the modified strand in both duplexes (the adduct is embedded within the same sequence context) with the buckling of the Watson-Crick [BP]dA6.dT17 base pair more pronounced in the (+)-cis-anti-[BP]dA.dT 11-mer duplex compared to its Watson-Crick [BPh]dA.dT17 base pair in the (+)-trans-anti-[BPh]dA.dT 11-mer duplex. The available structural studies of covalent polycyclic aromatic hydrocarbon (PAH) carcinogen-DNA adducts point toward the emergence of a general theme where distinct alignments are adopted by PAH adducts covalently linked to the N(6) of adenine when compared to the N(2) of guanine in DNA duplexes. The [BPh]dA and [BP]dA N(6)-adenine adducts intercalate their polycyclic aromatic rings into the helix without disruption of their modified base pairs. This may reflect the potential flexibility associated with the positioning of the covalent tether and the benzylic ring of the carcinogen in the sterically spacious major groove. By contrast, such an intercalation without modified base pair disruption option appears not to be available to [BP]dG N(2)-guanine adducts where the covalent tether and the benzylic ring are positioned in the more sterically crowded minor groove. In the case of [BP]dG adducts, the benzopyrenyl ring is either positioned in the minor groove without base pair disruption, or if intercalated into the helix, requires disruption of the modified base pair and displacement of the bases out of the helix.