A functional polymorphism in the MAOA gene promoter (MAOA-LPR) predicts central dopamine function and body mass index

Variation in brain monoaminergic activity is heritable and modulates risk of alcoholism and other addictions, as well as food intake and energy expenditure. Monoamine oxidase A deaminates the monoamine neurotransmitters serotonin, dopamine (DA), and noradrenaline. The monoamine oxidase A (MAOA) gene (Xp11.5) contains a length polymorphism in its promoter region (MAOA-LPR) that putatively affects transcriptional efficiency. Our goals were to test (1) whether MAOA-LPR contributes to interindividual variation in monoamine activity, assessed using levels of cerebrospinal fluid (CSF) monoamine metabolites; and (2) whether MAOA-LPR genotype influences alcoholism and/or body mass index (BMI). Male, unrelated criminal alcoholics (N=278) and controls (N=227) were collected from a homogeneous Finnish source population. CSF concentration of 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) were available from 208 participants. Single allele, hemizygous genotypes were grouped according to inferred effect of the MAOA alleles on transcriptional activity. MAOA-LPR genotypes had a significant effect on CSF HVA concentration (P=0.01) but explained only 3% of the total variance. There was a detectable but nonsignificant genotype effect on 5-HIAA and no effects on MHPG. Specifically, the genotype conferring high MAOA activity was associated with lower HVA levels in both alcoholics and controls, a finding that persisted after accounting for the potential confounds of alcoholism, BMI, height, and smoking. MAOA-LPR genotype predicted BMI (P<0.005), with the high-activity genotype being associated with lower BMI. MAOA-LPR genotypes were not associated with alcoholism or related psychiatric phenotypes in this data set. Our results suggest that MAOA-LPR allelic variation modulates DA turnover in the CNS, but does so in a manner contrary to our prior expectation that alleles conferring high activity would predict higher HVA levels in CSF. Our results are consistent with an emerging literature that suggests greater complexity in how variation in MAOA expression alters monoaminergic function. Finally, our work suggests that MAOA may be involved in the regulation of BMI. Independent samples are necessary to confirm this preliminary finding.

Multi-institutional phase 2 study of TLK286 (TELCYTA, a glutathione S-transferase P1-1 activated glutathione analog prodrug) in patients with platinum and paclitaxel refractory or resistant ovarian cancer

The purpose of this study was to determine the safety and efficacy of TLK286 (TELCYTA(TM)), a glutathione analog prodrug, in patients with platinum and paclitaxel refractory or resistant ovarian carcinoma. Thirty-six patients with measurable disease were enrolled. TLK286 was administered at 1000 mg/m2 intravenously every 3 weeks. The endpoints were objective response rate assessed by Response Evaluation Criteria in Solid Tumors (RECIST) and survival. Adverse events were graded using the National Cancer Institute Common Toxicity Criteria. Thirty-four platinum refractory or resistant patients (94%) were evaluable for objective tumor response. Five patients (15%) had objective tumor responses, including one durable complete response (CR) of greater than 3 years and continuing. The disease stabilization rate was 50%, including one CR (3%), four partial responses (12%), and 12 durable disease stabilizations (35%). Responses were accompanied by improvement in clinical symptoms and Eastern Cooperative Oncology Group Performance Status (ECOG PS) and decline in CA125 levels. Median survival was 423 days with survival of 60% at 1 year and 40% at 18 months. TLK286 was well tolerated in this population. TLK286 is an active agent in chemotherapy-resistant ovarian cancer. Further studies of TLK286 in platinum and paclitaxel refractory or resistant ovarian cancer are in progress.

Information and risk perception: a dynamic adjustment process

It is common in catastrophic food-contamination events that consumers fail to adjust instantaneously to a normal consumption level. One explanation is that consumers only gradually accept new positive information as being trustworthy. The gradual establishment of the trustworthiness of the released information depends on both positive and negative media coverage over time. We examine the individual "trust" effects by extending the prospective reference theory (Viscusi, 1989) to include a dynamic adjustment process of risk perception. Conditions that allow aggregation of changes in risk perceptions across individuals are described. The proposed model describes a general updating process of risk perceptions to media coverage and can be applied to explain the temporal impact of media coverage on consumption of a broad range of goods (food or nonfood). A case study of milk contamination is conducted to demonstrate consumer demand adjustment process to a temporarily unfavorable shock. The results suggest that effects of positive and negative information to adjustment of consumption and risk perception are asymmetric over time.

Linkage of antisocial alcoholism to the serotonin 5-HT1B receptor gene in 2 populations

BACKGROUND

In mice, quantitative trait locus studies and behavioral evaluation of animals deleted for 5-HT1B have implicated this serotonin autoreceptor in alcohol consumption and aggressive behavior. We therefore investigated whether the 5-HT1B gene (HTR1B) is linked to alcoholism with aggressive and impulsive behavior in the human, as represented by 2 psychiatric diagnoses: antisocial personality disorder and intermittent explosive disorder comorbid with alcoholism.

METHODS

Linkage was first tested in 640 Finnish subjects, including 166 alcoholic criminal offenders, 261 relatives, and 213 healthy controls. This was followed by a study in a large multigenerational family derived from a Southwestern American Indian tribe (n=418) with a high rate of alcoholism. All subjects were psychiatrically interviewed, blind-rated for psychiatric diagnoses, and typed for a HTR1B G861C polymorphism and for a closely linked short-tandem repeat locus, D6S284. Linkage was evaluated in sib pairs, and by using an association approach in which pedigree randomization corrects for nonindependence of observations on related subjects.

RESULTS

In Finnish sib pairs, antisocial alcoholism showed significant evidence of linkage to HTR1B G861C (P=.04) and weak evidence with D6S284 (P=.06). By association analysis, the 183 Finnish antisocial alcoholics had a significantly higher HTR1B-861C allele frequency than the other 457 Finns we studied (P=.005). In the Southwestern American Indian tribe, significant sib pair linkage of antisocial alcoholism to HTR1B G861C (P=.01) was again observed, and there was also significant linkage to D6S284 (P=.01).

CONCLUSION

These results suggest that a locus predisposing to antisocial alcoholism may be linked to HTR1B at 6q13-15.

A tryptophan hydroxylase gene marker for suicidality and alcoholism

BACKGROUND

Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in the synthesis of serotonin. Low turnover rate of this monoamine neurotransmitter is associated with impaired impulse control. We previously reported that, in Finns, TPH genotype was associated with suicidality, a pathophysiological mechanism that may involve impaired impulse control.

METHODS

Association and sib-pair linkage analyses of a polymorphism in intron 7 of the TPH gene with suicidality, alcoholism, and the Karolinska Scales of Personality were conducted in 804 Finnish alcoholic offenders, controls, and their relatives, in a sample that included 369 sib pairs.

RESULTS

The association of the TPH 17 779C (L) allele to suicidality in impulsive offenders reported previously was replicated in a new group of Finnish offenders (P=.001, n=122). The intron 7 variant in the TPH gene showed significant evidence for linkage to suicidality (P=.006 in unaffected sib pairs), severe suicide attempts (P=.006 in unaffected sib pairs; regression: P=.01), alcoholism (P=.003 in unaffected sib-pairs; regression: P=.02), and Karolinska Scales of Personality socialization score (regression: P=.002).

CONCLUSIONS

The status of the TPH A779C allele as a marker for suicidality was replicated and linkage with alcoholism and Karolinska Scales of Personality socialization score was also observed. A functional variant(s) in or close to the TPH gene may predispose individuals to suicidality and other behaviors thought to be influenced by serotonin.

Bacterial genetic loci implicated in the Pseudomonas putida GR12-2R3--canola mutualism: identification of an exudate-inducible sugar transporter

Pseudomonas putida GR12-2R3 promotes the emergence and growth of diverse plant species. Analyses of TnphoA insertion mutations are revealing bacterial characteristics pertinent to the plant-microbe interaction. Pseudomonas putida PG269 is a TnphoA insertion derivative of GR12-2R3 that expresses canola seed exudate-inducible alkaline phosphatase (PhoA) activity. It promoted the growth of canola roots, as well as strain GR12-2R3, and outgrew its parent when they were cocultured in the presence of canola roots or in liquid seed exudate medium. (In contrast, mutant PG126 failed to promote canola root growth and was outgrown by its parent strain.) The PhoA activity of strain PG269 was induced by glucosamine and other sugars; glucosamine inhibited the growth of strain GR12-2R3 and stimulated the growth of strain PG269. Strain PG269 contained two TnphoA insertions: seiA1::TnphoA and seiB1::TnphoA. Strain PG312, which contained only insertion seiA1::TnphoA, shared all aspects of the PG269 phenotype, except the ability to outcompete strain GR12-2R3 during coculture. Insertion seiA1::TnphoA interrupted an open reading frame related in sequence to members of the MalF family of sugar transporter subunits. The PhoA-inducing fraction of canola seed exudate was hydrophilic, low in molecular weight, and heat stable. It cochromatographed with basic amino acids and amino sugars, and was inactivated by strains GR12-2R3 and PG269. Gene seiA may encode a subunit of an ABC transporter with broad specificity for glucose and related sugars whose expression can be induced by exudate sugars.

Developmental toxicity study of mangafodipir trisodium injection (MnDPDP) in New Zealand white rabbits

Mangafodipir trisodium injection (MnDPDP) is an intravenously administered manganese chelate undergoing clinical evaluation for magnetic resonance imaging contrast enhancement of the hepatobiliary system. The anticipated single clinical dose for adults is 5 micromol/kg body wt. MnDPDP, as well as the inorganic salt, MnCl2, was previously shown to induce a specific syndrome of skeletal abnormalities in rats. The syndrome malformations included angulated or irregularly shaped clavicle, femur, fibula, humerus, ilium, radius, scapula, tibia, and/or ulna. The objective of the present study was to assess the developmental toxicity of MnDPDP in a second mammalian species, the New Zealand White rabbit. MnDPDP was intravenously administered daily to groups of rabbits (22 per group) on Days 6 through 18 of pregnancy at doses of 0 (saline), 5, 20, 40, and 60 micromol/kg MnDPDP. Fetuses were examined on Day 29 of pregnancy for external, visceral, and skeletal abnormalities. Treatment with MnDPDP did not result in overt symptoms of maternal toxicity, and there were no significant effects on maternal body weight gains or feed consumption. The maternal no-observed-adverse-effect level (NOAEL), therefore, was 60 micromol/kg MnDPDP. Treatment with MnDPDP resulted in a significant increase in postimplantation loss at 60 micromol/kg, but there was no significant increase in external, visceral, or skeletal abnormalities at any dose. The developmental NOAEL for MnDPDP, therefore, was 40 micromol/kg. These results indicate that the developmental toxicity profile of MnDPDP differs considerably in the rat and rabbit. In the rat, this compound induces specific skeletal abnormalities, whereas in the rabbit, embryo/fetal toxicity is the most sensitive developmental endpoint with no evidence for the induction of specific skeletal abnormalities.

The positions of the sigma-factor genes, whiG and sigF, in the hierarchy controlling the development of spore chains in the aerial hyphae of Streptomyces coelicolor A3(2)

whiG and sigF encode RNA polymerase sigma factors required for sporulation in the aerial hyphae of Streptomyces coelicolor. Their expression was analysed during colony development in wild-type and sporulation-defective whi mutant strains. Each gene was transcribed from a single promoter. Unexpectedly, whiG mRNA was present at all time points, including those taken prior to aerial mycelium formation; this suggests that whiG may be regulated post-transcriptionally. Transcription of whiG did not depend upon any of the six known 'early' whi genes required for sporulation septum formation (whiA, B, G, H, I and J), placing it at the top of the hierarchy of whi loci. sigF expression appeared to be regulated at the level of transcription; sigF transcripts were detected transiently when sporulation septa were observed in the aerial hyphae. Transcription of sigF depended upon all six of the early whi genes, including whiG. The sigF promoter does not resemble the consensus sequence established for sigma WhiG-dependent promoters and E sigma WhiG did not transcribe from the sigF promoter in vitro. Consequently, the genetic dependence of sigF upon whiG is very likely to be indirect. These results show that there is a hierarchical relationship between sigma factors required for Streptomyces sporulation and also that at least five other genes are involved in this transcriptional network.

Early-onset alcoholics have lower cerebrospinal fluid 5-hydroxyindoleacetic acid levels than late-onset alcoholics

BACKGROUND

We investigated the interrelationships of age at onset of excessive alcohol consumption, family history of alcoholism, psychiatric comorbidity, and cerebrospinal fluid monoamine metabolite concentrations in abstinent, treatment-seeking alcoholics.

METHODS

We studied 131 recently abstinent alcoholics. Supervised abstinence was maintained on a research ward at the National Institutes of Health Clinical Center for a minimum of 3 weeks. All alcoholics received a low-monoamine diet for a minimum of 3 days before lumbar puncture. Lumbar punctures were performed in the morning after an overnight fast. Monamine metabolites and tryptophan in cerebrospinal fluid were quantified with liquid chromatography by means of electrochemical detection. Psychiatric diagnoses were established from blind-rated Schedule for Affective Disorders and Schizophrenia-Lifetime version interviews administered by a research social worker. Severity and age at onset of excessive alcohol consumption were documented with a structured lifetime drinking history questionnaire and with selected alcoholism screening questionnaires (CAGE and Michigan Alcoholism Screening Test). Family history of alcoholism was obtained from the probands.

RESULTS

A majority of the treatment-seeking, primarily white male alcoholics had a lifetime history of psychiatric disorders other than alcoholism. None fulfilled criteria for antisocial personality disorder. Early-onset alcoholics (onset of excessive consumption before 25 years of age) had a more severe course of alcoholism and lower mean cerebrospinal fluid 5-hydroxyindoleacetic acid concentration than late-onset alcoholics. Patients who reported both parents to be alcoholics had particularly low mean cerebrospinal fluid 5-hydroxyindoleacetic acid, homovanillic acid, and tryptophan concentrations.

CONCLUSION

Among treatment-seeking alcoholics, early age at onset is generally associated with a more severe course of alcoholism and lower cerebrospinal fluid 5-hydroxyindoleacetic acid concentration.

The effects of milling and processing on wheat contaminated with ochratoxin A

Samples of sound home-grown wheat (one hard and one soft milling) were obtained, cleaned, and gamma-irradiation used to reduce numbers of viable naturally-occurring fungi. Each sample was inoculated with a toxigenic strain of Penicillium verrucosum and monitored for ochratoxin A formation. When ochratoxin A had reached a level of 60 micrograms/kg, the samples were milled into ten fractions which were analysed for ochratoxin A by an HPLC method with immunoaffinity column clean-up. Each straight-run white flour was baked into bread which was analysed in the same way. Relationships between ochratoxin A levels in naturally-contaminated wheat and the products of milling and baking were established. The recovery of ochratoxin A in wholemeal compared with the cleaned wheat was essentially complete and no significant loss occurred on baking white or wholemeal flour into bread. Recoveries in the straight-run white flours, however, were only approximately one-third for the hard wheat and two-thirds for the soft wheat of the ochratoxin A in the uncleaned wheat. The reason for this was that a much higher proportion of the ochratoxin A was found in the bran and offal fractions from hard wheat than from soft. Conversely, a much higher proportion of the ochratoxin A was found in the reduction flour from soft wheat than from hard. Scouring was examined as a possible method of decontamination of wheat prior to milling. This process removes a proportion of the pericarp (bran coat) prior to milling. The results of the study confirmed that scouring reduced the ochratoxin A level in white and wholemeal flour three-fold for both the hard and soft wheat.

State legislative approaches to regulating the use of genetic information

As genetic testing becomes more prevalent and the uses for genetic information multiply, we are likely to witness more demand for comprehensive state legislation on the order of the Oregon law regulating the procedures for obtaining and using genetic information. In addition, the United States Senate has expressed an interest in the subject. The Senate Labor and Human Resources Committee reportedly agreed on August 2, 1995 to include in a health insurance reform bill (S. 1028) language prohibiting health plans from using genetic information when determining eligibility, continuation, enrollment, or contribution requirements. 4 BNA's Health Law Rep. at 1218 (Aug. 10, 1995). Insurance companies continue to maintain that genetic test results are simply another factor that should rightfully be used during underwriting, much as age, medical history, and physical examinations are routinely used today. Right to privacy advocates argue that genetic testing provides employers and insurance companies with too much information and offers a great potential for discrimination. As more states wrestle with this issue, these competing interests are likely to be debated in public forums throughout the country.

Relationship of genetically transmitted alpha EEG traits to anxiety disorders and alcoholism

We tested the hypothesis that a heritable EEG trait, the low voltage alpha (LV), is associated with psychiatric disorders. Modest to moderate evidence for genetic linkage of both panic disorder and the low voltage alpha trait to the same region of chromosome 20q has recently been reported, raising the issue of whether there is a phenotypic correlation between these traits. A total of 124 subjects including 50 unrelated index subjects and 74 relatives were studied. Alpha EEG power was measured and EEG phenotypes were impressionistically classified. Subjects were psychiatrically interviewed using the SADS-L and blind-rated by RDC criteria. Alcoholics were four times more likely to be LV (including so-called borderline low voltage alpha) than were nonalcoholic, nonanxious subjects. Alcoholics with anxiety disorder are 10 times more likely to be LV. However, alcoholics without anxiety disorder were similar to nonalcoholics in alpha power. An anxiety disorder (panic disorder, phobia, or generalized anxiety) was found in 14/17 LV subjects as compared to 34/101 of the rest of the sample (P < 0.01). Support for these observations was found in the unrelated index subjects in whom no traits would be shared by familial clustering. Lower alpha power in anxiety disorders was not state-dependent, as indicated by the Spielberger Anxiety Scale. Familial covariance of alpha power was 0.25 (P < 0.01). These findings indicate there may be a shared factor underlying the transmissible low voltage alpha EEG variant and vulnerability to anxiety disorders with associated alcoholism. This factor is apparently not rare, because LV was found in approximately 10% of unrelated index subjects and 5% of subjects free of alcoholism and anxiety disorders.

DRD2 dopamine receptor genotype, linkage disequilibrium, and alcoholism in American Indians and other populations

We defined interpopulation differences in the frequency of the dopamine D2 receptor DRD2/Taq1 A1 allele, which has previously been associated with alcoholism. Frequencies of the A1 allele in unrelated subjects were 0.18 to 0.20 (se = 0.02 to 0.03) in several Caucasian populations previously assessed, 0.38 (+/- 0.05) in American Blacks (n = 44), 0.63 (+/- 0.07) in Jemez Pueblo Indians (n = 23), and 0.80 (+/- 0.04) in Cheyenne Indians (n = 52). The existence of large interpopulation differences in the frequency of the Taq1 alleles suggests that associations to disease status could readily be generated or masked if disease and control groups were uneven in ethnic composition. To address the possibility that the 4-fold higher frequency of the A1 allele in Cheyenne Indians was related to an increased vulnerability to alcoholism in that population, 47 Cheyenne Indians were psychiatrically interviewed and blind-rated. However, there was no significant difference between interviewed controls (0.73 +/- 0.06, n = 24), subjects with alcoholism and/or drug abuse (0.74 +/- 0.06, n = 23) and noninterviewed population controls (0.87 +/- 0.05, n = 20). Legitimate association of the DRD2/Taq1 allele to alcoholism would presumably require it to be in linkage disequilibrium (nonrandom association) with a functional mutation at DRD2 or elsewhere. The level of disequilibrium would vary between populations and could place an upper bound on the strength of an association.(ABSTRACT TRUNCATED AT 250 WORDS)