The interference of polychlorinated biphenyls (Aroclor 1254) with membrane regulation of the activities of cytochromes P-450C21 and P-450(17) alpha,lyase in guinea-pig adrenal microsomes

Regulation of cytochromes P-450 21-hydroxylase (P-450C21) and P-450 17 alpha-hydroxylase/C17,20-lyase (P-450(17) alpha,lyase) activities and impairment of this regulation by Aroclor 1254 was studied in guinea-pig adrenal microsomes. In a membrane depleted system, a decrease in the normally predominant, P-450C21 activity and an increase in P-450(17) alpha,lyase activities was observed. The same deviations were observed in intact microsomes with increase in the reaction temperature (0-40 degrees C). Breaks in Arrhenius plots for activities of P-450C21 and P-450(17) alpha,lyase correlate with transition temperatures reported for the microsomal membrane. These results point to: (1) preference of a gel state membrane for catalytic expression of P-450C21 suggesting a clustered organization of this P-450 species with reductase; (2) preference of a fluid membrane for lyase activity suggesting a random collision mechanism for reduction of P-450(17) alpha,lyase. Aroclor 1254 introduced to reaction mixtures containing intact microsomes elicited basically the same changes as caused by depletion of the microsomal membrane or by increase in the incubation temperature. Lack of effect of Aroclor 1254 on P-450C21 and P-450(17) alpha,lyase activities in the membrane depleted system demonstrates that its interference with monooxygenase activities is mediated by the microsomal membrane. The similarities between altered cytochrome P-450 mediated activities in the presence of Aroclor 1254 and the deviations observed in the membrane depleted system or upon increase in the incubation temperature may suggest that this chemical exerts its impacts by influencing membrane fluidity.

Molecular cloning of mouse alcohol dehydrogenase-B2 cDNA: nucleotide sequences of the class III ADH genes evolve slowly even for silent substitutions

We have cloned and sequenced a cDNA encoding the mouse class III alcohol dehydrogenase, Adh-B2. Adh-B2 mRNA is detectable in all the mouse tissues tested. Class III ADHs are highly conserved: the deduced amino acid sequence of the mouse Adh-B2 is 91 to 97% identical to the human, horse and rat liver enzymes. The mouse Adh-B2 cDNA is 87% identical in nucleotide sequence to the human chi-ADH cDNA. Previously, a slower rate of evolutionary divergence of the amino acid sequences of class III ADH proteins was detected and ascribed to functional constraints upon the protein. Our analysis of the nucleotide sequences demonstrates that this cannot be the entire explanation, since the rate of silent (synonymous) nucleotide substitutions is also lower in the class III ADHs than in the class I ADHs.

Alcoholism and substance abuse among selected southern Cheyenne Indians

This family and small community-based study reports the occurrence of alcoholism and co-occurring substance abuse in Southern Cheyenne Indians living in western Oklahoma. Sociocultural factors complicate operationalization of clinical data into standard (DSM-III-R) psychiatric disorder terminology; understanding sociocultural factors is essential for assessing the high rate of addictive disorders in this group. To obtain reliable and valid clinical diagnoses, data from several sources were utilized within a blind rating system: 1) SADS-L, a clinician-administered research diagnostic instrument; 2) MAST; 3) relatives; 4) medical records; 5) other official documents. The sample consisted of 69 males (45 alcoholics) and 97 females (36 alcoholics). Among clinically significant substance abusers (moderate impairment of function), 22 of 24 were alcoholics. In non-alcoholics, mean MAST scores were 8.8 (males) and 5.1 (females); in alcoholics, 32.0 (males) and 38.7 (females). Mean age of onset on heavy use of alcohol was 20.1 yrs. (males) and 22.8 (females) (p = 0.047); among all alcoholics, 86% (males) and 64% (females) had early onset (< 25 yrs. old). When data from 98 unrelated subjects were analyzed separately, similar findings were observed except that mean age of onset of heavy use of alcohol was more discrepant between males and females, viz. 20.1 versus 22.8 yrs. (p = 0.02). Among those with substance abuse disorders, early age of onset was present in all but one female. In these Cheyenne, alcoholism is usually clinically severe and early in onset; it often co-occurs with substance abuse, also early in onset.

Linkage mapping of human polymorphic proteins identified by two-dimensional electrophoresis

Nineteen polymorphic lymphocyte proteins were previously detected by two-dimensional protein electrophoresis (2DE). In this report, we describe the genetic linkage mapping of six of these polymorphic proteins (PNIA1-PNIA6), the identification by genetic linkage of a seventh (glyoxalase 1 on 6p21), and support for the mapping of an eighth (plastin or LCP1) to near the ESD locus on Chr 13. PNIA1-PNIA6 were assigned, respectively, to 10q26, 16p13.3, 10q, 11p15, 3q, and 19q13. These genetic linkages were achieved by classical linkage analysis of 2DE protein charge polymorphisms to the panel of RFLPs previously typed in nine pedigrees in the Centre D'Etude du Polymorphisme Humain (CEPH) collection.

Induction of adult-type nicotinic acetylcholine receptor gene expression in noninnervated regenerating muscle

Expression of adult-type nicotinic acetylcholine receptors at the neuromuscular junction is thought to result from selective induction of their genes in endplate-associated nuclei due to local neurotrophic control. However, denervation studies indicate that endplate-specific expression can be maintained in the absence of the nerve. We investigated the role played by the basal lamina in this expression by assaying for the adult-type-specific epsilon RNA in noninnervated regenerating muscle. We found that this RNA is locally expressed beneath the old endplates after 10 days of regeneration. At earlier times epsilon RNA is also found in areas other than the endplate region. These results indicate that in adult muscle the basal lamina contains all the components necessary to direct nicotinic acetylcholine receptor gene expression to the endplate.

Genetic mapping of the beta 1 GABA receptor gene to human chromosome 4, using a tetranucleotide repeat polymorphism

As more coding loci for functional human genes are described, there is a growing need to identify DNA polymorphisms in specific genes. By examining DNA sequences within the introns of the beta 1 subunit of the gamma-aminobutyric acid receptor gene, GABARB1, we found a tetranucleotide repeat sequence (GATA). Amplification of this region by using PCR revealed seven alleles and a high degree of polymorphism (PIC = .75) in human populations. DNAs from the CEPH families were typed for the GABARB1 intron polymorphism and were analyzed with respect to 20 linked markers on chromosome 4. The results permit placement of GABARB1 on the linkage map of chromosome 4, between D4S104 and ALB. These results affirm that sequence analysis of noncoding segments included within or adjacent to functional genes has value as a strategy to detect highly informative polymorphisms.

3H-paroxetine binding in brains of alcoholics

High affinity 3H-paroxetine binding was studied in human frontal cortex and hippocampus obtained from normal controls and alcoholics. On the basis of Scatchard analyses, a significant decrease in the maximal number of binding sites (Bmax) was found in the hippocampus of alcoholics (n = 8) as compared with that of controls (n = 10) (mean +/- SD = 63 +/- 35 vs. 114 +/- 70 fmoles/mg protein). There was no significant difference in the dissociation constants (Kd) between the two groups. The presumed effect of chronic alcohol abuse on 3H-paroxetine binding may be region-specific since no significant difference in either Bmax or Kd for 3H-paroxetine binding was found in the frontal cortex between normal controls and alcoholics. No significant correlation of 3H-paroxetine binding with age or postmortem interval was observed. The decrease in 3H-paroxetine binding in the hippocampus of alcoholics is probably indicative of reduced density of serotonergic nerve terminals either as a preexisting condition or as a result of neuronal damage caused by ethanol or the sequelae of alcoholism, such as nutritional deficiencies.

Personality and cerebrospinal fluid monoamine metabolites in alcoholics and controls

Alcoholics as a group have been consistently reported to show differences from controls on various personality inventories. Moreover, neurobiologic substrates have been postulated to underlie personality dimensions. Therefore, we compared alcoholics with controls on measures of personality and investigated relationships between measures of personality and cerebrospinal fluid monoamine metabolite concentrations. The alcoholics were significantly different from controls on many personality measurements. There were significant, negative correlations between interview-derived lifetime aggression scores and cerebrospinal fluid concentrations of both the serotonin metabolite 5-hydroxyindoleacetic acid and the dopamine metabolite homovanillic acid. However, there were no significant correlations between any cerebrospinal fluid monoamine metabolite concentrations and scores on personality inventories.

Isolation and structural characterization of the murine tryptophan hydroxylase gene

The mouse tryptophan hydroxylase gene was isolated and its intron/exon boundaries and putative regulatory sequences identified. To isolate the gene a mouse mastocytoma cDNA clone encoding tryptophan hydroxylase was used to identify and isolate ten overlapping DNA fragments from a mouse genomic library. Restriction mapping and sequence analysis of the clones revealed that the gene contains 11 exons and covers a region of DNA of approximately 21 kb. The transcription initiation site was mapped and the major site of initiation yields an untranslated leader sequence of 124 nucleotides. A minor initiation site is located 9 nucleotides 3' of the major site. The 5' untranslated sequence is interrupted by the first intron. Analysis of the sequence upstream of the initiation site showed the presence of several putative promoter and regulatory sequences. Nine of the ten intron/exon boundaries of tryptophan hydroxylase are conserved with tyrosine hydroxylase and phenylalanine hydroxylase, further delineating the evolutionary relationship of these three genes.

Cytochrome P-450 mediated metabolism of progesterone by adrenal microsomes of PCB-treated and untreated barn owl (Tyto alba) and marsh turtle (Mauremys caspica) in comparison with the guinea-pig

1. Significant differences between species were observed in the profile of steroids produced from progesterone by adrenal microsomes as well as in the effects elicited by Aroclor 1254 on cytochrome P-450-mediated activities. 2. In the guinea-pig, the major metabolites were products of the corticosteroid pathway but products of the androgenic pathway were also detected; in the barn owl products of both pathways were also formed while in the marsh turtle only products of the corticosteroid pathway were detected. 3. The effect of Aroclor 1254 on P-450C21 activity in the turtle and barn owl was inductive in contrast to the inhibitory effect observed in the guinea-pig.

Identifying genes determining trait differences in behavior and drug response: a comment on 'Quantitative trait loci and psychopharmacology'

In Plomin, McClearn and Gora-Maslak's target article (see also Science 248: 183-188, 1990), reverse genetic approaches are emphasized for locating genes determining behavioral and pharmacogenetic traits. Furthermore, prospects for such an undertaking are presented pessimistically in that behavioral traits are asserted to be polygenic (due to the simultaneous action of variant alleles at multiple loci) and are conceptualized as being determined in large part by unshared environmental factors. We disagree with Plomin et al. in three major areas and argue the following:(1) Forward genetic approaches involving candidate locus analysis and detailed analysis of the phenotype are of primary importance for isolating genes for behavioral traits, as for other genetic traits.(2) Virtually all physiologic processes and metabolic pathways involve sets of genes, resulting in genetic heterogeneity (multiple genetic origins for a trait). However, polygenicity is approximately as unusual for behavioral traits as for other traits.(3) Heritability analyses underestimate the extent to which behavioral traits are amenable to genetic analysis and have been misinterpreted to overestimate the importance of environmental factors.

Population and pedigree studies reveal a lack of association between the dopamine D2 receptor gene and alcoholism

Using the dopamine D2 receptor clone lambda hD2G1, Blum et al recently found that the D2/Taq I allele (A1) was present in 69% of 35 deceased alcoholics but in only 20% of an equal number of controls. To assess this association further, we evaluated the D2/Taq I polymorphism and a single-strand conformation polymorphism detected by polymerase chain reaction and nondenaturing gel electrophoresis (PCR-SSCP) of the 3' noncoding region of the D2 receptor gene. We studied 40 unrelated white alcoholics, 127 racially matched controls, and two white pedigrees. The Schedule for Affective Disorders and Schizophrenia-Lifetime Version (SADS-L) clinical diagnostic interviews were rated blindly by two clinicians. The SADS-L interviews and other data were then used to ascertain diagnoses according to the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition (DSM-III-R) criteria. Alcoholics were subtyped according to age of onset, severity, presence of antisocial personality, and family history. No significant differences in either D2/Taq I or PCR-SSCP allele frequencies were observed between alcoholics, subpopulations of alcoholics, or controls. The PCR-SSCP polymorphism provided independent information against linkage at the D2 receptor locus. Several recombinants between the D2/Taq I locus and alcoholism were observed in two white families with an alcoholic parent who possessed the A1 allele. This study does not support a widespread or consistent association between the D2 receptor gene and alcoholism.

Profile of bronchospastic disease in Puerto Rican patients in New York City. A possible relationship to alpha 1-antitrypsin variants

A high prevalence of asthmalike symptoms was noted among patients of Puerto Rican descent attending Beth Israel and North Central Bronx Medical Centers in New York City, as compared with other ethnic groups. An evaluation of family and medical histories, pulmonary function data, and alpha 1-antitrypsin phenotypes was undertaken in such Puerto Rican patients and control subjects without asthma. The patients showed a higher proportion of MS and MV phenotypes. All the patients in both MM and variant phenotype groups, with the exception of four MM patients, had features indicative of asthma, with labile airway obstruction, and elevated serum immunoglobulin E and eosinophil levels. The latter was significantly higher in the patients with variant phenotypes than in MM patients. Patients with alpha 1-antitrypsin variants also had much shorter smoking histories as compared with the MM group, and all reported histories of asthma in first-degree relatives, as compared with 66% among the MM patients. We conclude that there is an increased incidence of asthma among Puerto Ricans in New York City, and that the antitrypsin variant phenotypes (specifically S and V) play a role in this incidence and its expression.

Molecular genetic divergence of orang utan (Pongo pygmaeus) subspecies based on isozyme and two-dimensional gel electrophoresis

The orang utan (Pongo pygmaeus), as currently recognized, includes two geographically separated subspecies: Pongo pygmaeus pygmaeus, which resides on Borneo, and P. p. abelii, which inhabits Sumatra. At present, there is no known route of gene flow between the two populations except through captive individuals which have been released back into the wild over the last several decades. The two subspecies are differentiated by morphological and behavioral characters, and they can be distinguished by a subspecies specific pericentric chromosomal inversion. Nei-genetic distances were estimated between orang utan subspecies, gorilla, chimpanzee and humans using 44 isozyme loci and using 458 soluble fibroblast proteins which were resolved by two-dimensional gel electrophoresis. Phenetic analysis of both data sets supports the following conclusions: the orang utan subspecies distances are approximately 10 times closer to each other than they are to the African apes, and the orang utan subspecies are approximately as divergent as are the two chimpanzee species. Comparison of the genetic distances to genetic distance estimates done in the same laboratory under identical conditions reveals that the distance between Bornean vs. Sumatran orang utans is 5-10 times the distance measured between several pairs of subspecies including lions, cheetahs, and tigers. Near species level molecular genetic distances between orang utan subspecies would support the separate management of Bornean and Sumatran orang utans as evolutionary significant units (Ryder 1987). Evolutionary topologies were constructed from the distance data using both cladistic and phenetic methods. The majority of resulting trees affirmed previous molecular evolutionary studies that indicated that man and chimpanzee diverged from a common ancestor subsequent to the divergence of gorilla from the common ancestor.

Noradrenergic control of the synthesis of two rat pineal proteins

Pineal physiology is controlled by norepinephrine released from sympathetic nerves terminating in the gland. In the present study, the effect of norepinephrine on the labelling of specific proteins was investigated by incubating glands with [35S]methionine and then resolving the proteins by two-dimensional polyacrylamide gel electrophoresis; the patterns were analyzed by computer-assisted image analysis. The most prominent effects of norepinephrine were distinct and consistent increases in the labelling of two proteins (37 kDa, pI = 6.0, 50 kDa, pI = 6.0), designated adrenergically induced protein (AIP 37/6 and AIP 50/6). In both cases, norepinephrine was effective at low concentrations (EC50 = 10 nM). Pharmacological studies indicated that the effects of norepinephrine on both proteins involved a beta-adrenergic receptor, and that cyclic AMP was the second messenger. Pulse-chase labelling experiments revealed that these effects of norepinephrine did not involve post-translational modification of previously labelled precursor proteins, but depended upon de novo synthesis of protein. An inhibitor of mRNA synthesis, actinomycin-D, was found to block the effect of norepinephrine on AIP 50/6 but not on AIP 37/6, suggesting that norepinephrine acted on AIP 50/6 via a transcriptional mechanism and on AIP 37/6 via a translational mechanism. These in vitro studies were extended into in vivo investigations by measuring silver-stained AIP 37/6 in the two-dimensional gels. Changes in the amount of AIP 37/6 in pineal glands were studied in response to treatments which block the adrenergic stimulation of the gland, including exposure to constant lighting or removal of the superior cervical ganglia. Both treatments reduced AIP 37/6 by 50-75% in 8 weeks. These observations, together with those from in vitro studies, suggest that the amount of AIP 37/6 in the pineal gland is regulated by norepinephrine; and further, that norepinephrine acts through a beta-adrenergic-cyclic AMP mechanism to control AIP 37/6 synthesis at a translational level.

Characterization and chromosomal mapping of a cDNA encoding tryptophan hydroxylase from a mouse mastocytoma cell line

A cDNA library was constructed from RNA prepared from P815 mouse mastocytoma cells and screened for tryptophan hydroxylase. An essentially full-length clone that recognizes a major mRNA species of 1.9 kb in mastocytoma cell lines and in pineal gland, duodenum, and brainstem of the mouse was obtained. The predicted amino acid sequence of this mouse mastocytoma clone showed 97 and 87% identity, respectively, with tryptophan hydroxylase clones isolated from rat and rabbit pineal glands, but the mouse clone contains an unusual 3-amino-acid duplication near the N-terminus and lacks a phosphorylation site. A fragment of the cDNA produced an enzymatically active protein when expressed in Escherichia coli, thus demonstrating that the catalytic domain is included in the C-terminal 380 amino acids. The mouse tryptophan hydroxylase locus, termed Tph, was mapped by Southern blot analysis of somatic cell hybrids and by an interspecific backcross to a position in the proximal half of chromosome 7. Because TPH has been mapped to human chromosome 11, this assignment further defines regions of homology between these mouse and human chromosomes.

Inhibition by adenosine 3':5'-monophosphate of eicosanoid and platelet-activating factor biosynthesis in the mouse PT-18 mast cell

A mouse spleen-derived mast cell line (PT-18) was employed to examine the mechanisms of adenosine 3':5'-monophosphate (cAMP)-mediated inhibition of antigen-induced lipid mediator biosynthesis. Specifically, we tested the hypothesis that increasing cAMP in mast cells inhibits lipid mediator biosynthesis by a mechanism independent of effects on histamine release (degranulation) or changes in cytosolic calcium concentration. Forskolin inhibited antigen-induced prostaglandin D2 (PGD2), leukotriene C4 (LTC4), and leukotriene B4 (LTB4) production by 30-50%. In contrast, forskolin had no inhibitory effect on antigen-induced increases in cytosolic calcium concentration, as monitored by the calcium indicator fura-2, or histamine release from the cells. The combination of the phosphodiesterase inhibitor isobutylmethylxanthine with forskolin inhibited the antigen-induced production of PGD2 and LTC4 by 90-100% and histamine release by about 60%. These responses were accompanied by a virtual abolition of the antigen-induced increase in cytosolic calcium. To test further the hypothesis that increasing cAMP can lead to inhibition of lipid mediator biosynthesis in the absence of effects on cytosolic calcium, we employed the calcium ionophores A23187 and ionomycin. Forskolin alone or in combination with isobutylmethylxanthine had no effect on ionophore-induced increases in cytosolic calcium but effectively inhibited leukotriene biosynthesis. In addition, increasing cyclic AMP led to an inhibition of ionophore-induced production of platelet-activating factor and liberation of arachidonic acid. These data suggest that a relatively modest increase in cAMP-dependent protein kinase activity in mast cells leads to inhibition of the lipase-catalyzed cleavage of arachidonic acid from membrane phospholipids in the absence of measurable effects on either histamine release or changes in cytosolic calcium concentration. This effect results in a selective inhibition of the biosynthesis of lipid mediators including LTC4, LTB4, PGD2, and platelet-activating factor.

Dietary treatment of hypercholesterolemia

Diet is the first line of treatment for hypercholesterolemia. Patients should be encouraged to make simple and stepwise changes in their diets to lower elevated cholesterol levels. General dietary guidelines from the American Heart Association (AHA) Step-One Diet include limiting the amount of total fat to less than 30% of total calories, decreasing cholesterol intake to less than 300 mg/day, and adjusting caloric intake to levels required to attain or maintain ideal body weight. Diets must be individualized to meet therapeutic needs within the limits of the patient's abilities, knowledge, and motivation.