Evaluation of an HIV prevention intervention designed for African American Women: results from the SISTA Community-Based Organization Behavioral Outcomes Project

One of the Centers for Disease Control and Prevention's strategies for addressing racial disparities within the HIV epidemic is to support the implementation of HIV prevention behavioral interventions designed for African Americans. One such intervention is Sisters Informing Sisters about Topics on AIDS (SISTA), a culturally relevant and gender-specific, five-session, group-level, HIV prevention intervention designed for African American women. In 2008, the Centers for Disease Control and Prevention funded five community-based organizations to conduct outcome monitoring of SISTA to assess the outcomes associated with implementation in the field. Using a 90-day recall, demographic and sexual risk data were collected from participants at baseline and at 90 and 180 days post-intervention. Findings reveal that women participating in SISTA (n = 432) demonstrated a significant reduction in sexual risk between baseline and both follow-up time points for each of the six outcomes being measured (e.g., any unprotected sex, all protected sex).

Recognition of dopamine transporters by antipeptide antibodies

Hemocyanin-conjugated peptides corresponding to amino acid sequences from 14 different regions of the rat dopamine transporter were used to immunize rabbits and the resulting antisera were tested for dopamine transporter recognition. Eleven of the peptide sequences produced antipeptide antibodies detectable with ELISA assays. Sera directed against four of the peptides immunoprecipitated striatal transporters photoaffinity labeled with [(125)I]DEEP. Antisera directed against a peptide sequence at the C-terminal region of the transporter's putative second extracellular loop, "peptide 5," recognized photolabeled dopamine transporter protein from rat, dog, and human basal ganglia. These sera also recognized dopamine transporters from rat striatum in immunoblots; however, no reaction was found when rat cerebellum or frontal cortical tissue was used. These results provide further evidence that the cloned cDNA and its deduced amino acid sequence represents the protein expressed in brain and highlights the regions of the transporter which may be promising sites for the development of high-affinity antibodies.

Evaluation of an HIV prevention intervention for African Americans and Hispanics: findings from the VOICES/VOCES Community-based Organization Behavioral Outcomes Project

There is limited knowledge about whether the delivery of evidence-based, HIV prevention interventions in 'real world' settings will produce outcomes similar to efficacy trial outcomes. In this study, we describe longitudinal changes in sexual risk outcomes among African American and Hispanic participants in the Video Opportunities for Innovative Condom Education and Safer Sex (VOICES/VOCES) program at four CDC-funded agencies. VOICES/VOCES was delivered to 922 high-risk individuals in a variety of community settings such as substance abuse treatment centers, housing complex centers, private residences, shelters, clinics, and colleges. Significant risk reductions were consistently observed at 30- and 120-days post-intervention for all outcome measures (e.g., unprotected sex, self-reported STD infection). Risk reductions were strongest for African American participants, although Hispanic participants also reported reducing their risky behaviors. These results suggest that, over a decade after the first diffusion of VOICES/VOCES across the U.S. by CDC, this intervention remains an effective tool for reducing HIV risk behaviors among high-risk African American and Hispanic individuals.

Organic labeling influences food valuation and choice

Everyday we choose between a variety of different food items trying to reach a decision that fits best our needs. These decisions are highly dependent on the context in which the alternatives are presented (e.g. labeling). We investigate the influence of cognition on food evaluation, using an fMRI experiment in which subjects saw and bid on different foods labeled with (or without) a widely known German emblem for organically produced food. Increased activity in the ventral striatum was found for foods labeled "organic" in comparison to conventionally labeled food. Between-subject differences in activity were related to actual everyday consumption behavior of organic food.

Measurement of hypocretin/orexin content in the mouse brain using an enzyme immunoassay: the effect of circadian time, age and genetic background

The hypocretins (1 and 2) have emerged as key regulators of sleep and wakefulness. We developed a high-throughput enzyme immunoassay (EIA) to measure total brain hypocretin levels from large numbers of mice. Hypocretin levels were not altered by circadian time or age. However, significant differences in one or both hypocretin peptides were observed between different mouse strains. We studied hypocretin levels in knockout and transgenic mouse models with obesity, circadian gene mutations or monoaminergic defects. Compared to controls, only histamine receptor knockouts had lower hypocretin levels. This was most pronounced in H1 receptor knockouts suggesting the existence of a positive feedback loop between hypocretin and histaminergic neurons.

Genetic perspectives on the serotonin transporter

The serotonin transporter (5-HTT) is most well known as the site of action of the serotonin reuptake inhibitors, which were initially developed as antidepressants, but now are the most widely used agents in the treatment of many additional neuropsychiatric and related disorders. The discovery that the gene that expresses the 5-HTT possesses a functional promoter-region polymorphism, which is associated with temperament and personality traits such as anxiety and negative emotionality as well as some behaviors, led to many studies examining this polymorphism in individuals with different neuropsychiatric disorders. The subsequent development of mice with a targeted disruption of the 5-HTT in our laboratory has provided an experimental model to examine the many consequences of diminished (in +/-, heterozygote mice) or absent (in -/-, homozygote knockout mice) function of the 5-HTT. The 5-HTT-deficient mice were also crossed with other knockout mice, allowing the study of multiple neurobiologic dysfunctions. As multiple genes are probably involved in the expression of complex behaviors such as anxiety, as well as neuropsychiatric disorders, these more genetically complex mice may more closely model disorders with complex etiologies. Thus, the combination of these comparative human and mouse studies may extend the opportunities to examine genetic alterations from a novel "bottom-up" approach [gene knockout or partial gene knockout in a combinational gene x gene x (yet unknown) gene approach], which is complementary to the traditional "top-down" genetic approach based upon studies of individuals with diagnosed neuropsychiatric disorders and their family members.

Haplotype study of three polymorphisms at the dopamine transporter locus confirm linkage to attention-deficit/hyperactivity disorder

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is often treated using methylphenidate, a psychostimulant that inhibits the dopamine transporter. This led E.H. Cook and colleagues to consider the dopamine transporter locus (DAT1) as a primary candidate gene for ADHD. That group reported a significant association between ADHD and the 480-base pair (bp) allele of the variable number of tandem repeats (VNTR) polymorphism located in the 3' untranslated region of the DAT1 gene. This association was later replicated in additional studies.

METHODS

The DAT1 gene has additional common polymorphisms in intron 9 and exon 9. We investigated the possibility of linkage of DAT1 and ADHD using the VNTR polymorphism and two additional common polymorphisms in 102 nuclear families with an ADHD proband. Using the transmission disequilibrium test, we examined the transmission of the alleles of each of these polymorphisms, as well as the haplotypes of the polymorphisms.

RESULTS

We did not observe significant evidence for the biased transmission of the alleles of either the VNTR or the additional two polymorphisms when examined individually, although there was a trend for the biased transmission of the 480-bp allele of the VNTR. When we examined the haplotypes of the three polymorphisms we found significant evidence for biased transmission of one of the haplotypes containing the 480-bp VNTR allele. We also genotyped six additional DNA sequence variants of the DAT1 gene. However, these variants were not sufficiently polymorphic in our sample to be informative. Two of the DNA variants that result in an amino acid change, Ala559Val and Glu602Gly, were not observed in our sample.

CONCLUSIONS

Our results support previous findings of an association between the DAT1 gene and ADHD.

Two distinctly different sperm storage organs in female Dysdera erythrina (Araneae: Dysderidae)

The haplogyne spider D. erythrina possesses two distinctly different sperm storage organs: a bilobed anterior spermatheca and a large, sac-like posterior diverticulum. The glandular equipment of both storage types is markedly different: the glandular tissue of the spermatheca is composed of complicated glandular units comprising a cuticular ductule and three canal cells (class 3 cells) whereas the glandular tissue of the posterior diverticulum is composed of simple gland cells that discharge their product through the cuticle (class 1 cells). Thus, the glandular products produced differ, leading to different storage conditions for the spermatozoa from copulation to egg laying. It is suggested that multiple organ types have evolved to facilitate specialization in short-term and long-term storage and to allow (posterior diverticulum) or prevent (spermatheca) males from accessing previously stored sperm.

Enhanced delta-opioid receptor-mediated antinociception in mu-opioid receptor-deficient mice

Inflammatory hyperalgesia was induced in wild-type, heterozygous and mu-opioid receptor knockout mice after an intraplantar injection of complete Freund's adjuvant. micro-Opioid receptor knockout mice exhibited faster recovery from hyperalgesia as compared to heterozygous (P<0.05) and wild-type (P<0.01) mice. Naloxone restored hyperalgesia in all genotypes. Naltrindole (delta-opioid receptor-selective antagonist) partially restored the hyperalgesia only in mu-opioid receptor knockout mice (P<0.001). Nor-binaltorphimine (kappa-opioid receptor-selective antagonist) had no effect. The mu-opioid receptor-selective agonist, [D-Ala(2), MePhe(4),Gly-ol(5)]enkephalin (DAMGO), reduced the hyperalgesia in heterozygous and wild-type but not in mu-opioid receptor knockout mice while U69,593 ¿(+)-(5alpha,7alpha, 8beta)-N-methyl-N-[7-(1-pyrrolidinyl)-1-oxaspiro[4. 5]dec-8-yl]-benzeneacetamide, kappa-opioid receptor-selective¿ produced similar effects in all mice. The delta-opioid receptor-selective agonists, [D-Pen(2), D-Pen(5)]enkephalin (DPDPE) and deltorphin ([D-Ala(2)]deltrophin-II), produced significantly greater antihyperalgesia in knockout mice (P<0.05). The findings suggest that mu-opioid receptors may be involved in the persistence of inflammatory hyperalgesia and that a delta-opioid receptor-mediated compensatory mechanism in the absence of the mu-opioid receptor is activated by persistent hyperalgesia.

Follow-up of hepatitis C virus RNA in peripheral blood mononuclear cells during interferon therapy

Mononuclear cells can be infected in vitro by hepatitis C virus and the viral RNA can be detected in mononuclear cells of chronically infected patients. It was suggested that the virus could persist in the mononuclear cells of some patients treated by interferon. The aim of this study was to follow the presence of viral RNA in the plasma and peripheral blood mononuclear cells of 16 chronically infected patients treated by alpha 2b interferon for 1 year. The RNA was detected by reverse transcription followed by nested PCR and quantified using the branched DNA method at regular intervals for at least one year. Before PCR, the mononuclear cells were treated by RNase and trypsin in order to eliminate the viral particles that could be stuck at the cell surface. Six patients were non responders and had persistent plasmatic viral RNA during the treatment. Two patients were good responders and had persistently negative PCR in both plasma and mononuclear cells. Eight patients had initial negativation of plasmatic hepatitis C virus RNA but showed a relapse characterized by positive plasmatic PCR. Positive PCR in mononuclear cells despite negativity of plasmatic PCR was noted 18 times in 8 patients. Persistently positive PCR in mononuclear cells in absence of detectable viraemia was followed by a virological relapse in 5 of these patients. This study confirms that hepatitis C virus RNA can be detected in mononuclear cells despite negative plasmatic PCR in patients treated by interferon. Moreover, the persistence of viral RNA in peripheral mononuclear cells could be a predictive factor of treatment failure. Our data also suggest that detection of viral RNA in mononuclear cells is probably not only due to passive virus adsorption from plasma.

Characterization of mechanical withdrawal responses and effects of mu-, delta- and kappa-opioid agonists in normal and mu-opioid receptor knockout mice

Clinical and experimental observations suggest that opiates can exert different influences on the perception of stimuli from distinct sensory modalities. Thermally-induced nociception is classically responsive to opiate agonists. mu-Opioid receptor-deficient transgenic mice are more sensitive to thermal nociceptive stimuli and morphine fails to attenuate the nociceptive responses to thermal stimuli in these animals. To enhance our understanding of opiate influences on mechanical sensitivity, we have examined withdrawal responses to a sequence of ascending forces of mechanical stimuli in mice with normal (wild type), half-normal (heterozygous) and absent (homozygous) mu-opioid receptor levels. We report data from mice examined without drug pretreatment or following pretreatment with morphine, the selective kappa-opioid agonist, U50488H, and the selective delta-opioid agonist, DPDPE. Saline-pretreated mice of each genotype displayed similar, monotonically increasing frequency of withdrawal responses to the graded stimuli. Subcutaneously administered morphine produced a dose-dependent reduction in withdrawal responses in wild type and heterozygous mice, but had no significant effect in homozygous mice. Intraventricular administration of DPDPE also reduced the frequency of paw withdrawal (FPW) in wild type mice, but not in homozygous mice. In contrast, systemic U50488H produced a dose-dependent attenuation of paw withdrawal in both wild type and homozygous mice. These findings suggest that (1) interactions of endogenous peptides with mu-opioid receptors may not play a significant role in the response to mechanical stimuli in drug-free animals, and (2) deficiency of mu-opioid receptors has no functional consequence on the response to the prototypical kappa-opioid receptor agonist, but decreases responses to the prototypical mu- and delta-opioid receptor agonists.

Mating behaviour in the cellar spider, Pholcus phalangioides, indicates sperm mixing

In insects and spiders, the pattern of sperm priority is often attributed to the shape of the spermathecae and should entail marked consequences for mating behaviour. Since last-male priority is assumed to occur in haplogyne spiders such as the cellar spider, females of this species are predicted to be more attractive to males shortly before, than shortly after, egg laying and males may guard females after copulation until oviposition. To test these predictions, I individually marked spiders of a natural population and recorded their position and the distance between potential mating partners twice a day over 100 days. The distance between female and male was taken as a measure of the female's attractiveness. The behaviour of cellar spider males was not in accordance with the predictions; females were visited throughout the observation period with no significant increase in attractiveness before egg laying and there was no evidence for mate guarding. However, female attractiveness was correlated with female size, which was correlated with the number of eggs laid. Behaviour and genital morphology suggest sperm mixing occurs in this species. This is discussed in the light of conflicting data on sperm priority. Copyright 1998 The Association for the Study of Animal Behaviour.

Murine vesicular monoamine transporter 2: molecular cloning and genomic structure

The principal brain vesicular monoamine transporter (VMAT2) pumps monoamines including dopamine, norepinephrine, serotonin and histamine from neuronal cytoplasm into synaptic vesicles and is implicated in actions of certain psychostimulants and selective neurotoxins. To improve understanding of this gene and its regulation, and to facilitate study of the roles played by this important molecule in mouse genetic models, we have cloned murine VMAT2 cDNA and genomic sequences. A 4.2-kb mouse VMAT2 cDNA hybridized to a 4.3-kb mRNA expressed chiefly in brainstem. Murine cDNA and genomic DNA analyses reveal an open reading frame of 1551 bp encoding 517 amino acids that display 92, 96 and 60% amino-acid identity with human and rat VMAT2, and rat vesicular acetylcholine transporter sequences, respectively. This open reading frame is distributed over 15 of 16 identified exons, and spans > 35 kb of genomic DNA. A major transcriptional initiation site is identified 107 bp 5' to the translational initiation ATG codon using primer extension/5' rapid amplification of cDNA ends. Sequences immediately 5' of this putative transcription start site lack 'TATA' or 'CATT' boxes, but contain consensus sequences that may bind cAMP response element, Sp1, AP2 and other transcription factors. Identification of these genomic sequences facilitates construction of homologous recombinant mice, provides a template for gene structures in the vesicular transporter family, and identifies sequences elements that could contribute to the specific patterns of regulated VMAT2 expression in monoaminergic neurons.

Lymphocyte reactivity to hepatitis C virus (HCV) antigens shows evidence for exposure to HCV in HCV-seronegative spouses of HCV-infected patients

Lymphocyte reactivity against hepatitis C virus (HCV) antigens was studied in 20 couples in which 1 member had chronic hepatitis C. This was done to investigate the possibility of HCV transmission between spouses that was not followed by seroconversion. Twenty healthy subjects without any risk factors for HCV transmission served as negative controls. All the patients' spouses and the healthy controls were negative for HCV RNA and for anti-HCV antibody. Lymphocytes were cultured with recombinant HCV core and nonstructural antigens (c22, c33, c100, c200, and NS5) and with control antigens (sperm whale myoglobin, chicken lysozyme, and superoxide dismutase). Lymphocytes from 10 patients and 4 seronegative spouses proliferated in the presence of at least one HCV antigen. No proliferation was shown with nonspecific antigens or in the control group. This study gives evidence for possible in vivo priming with HCV antigens that did not lead to seroconversion in spouses of HCV-positive patients.

HIV increases hepatitis C viraemia irrespective of the hepatitis C virus genotype

In case of coinfection with hepatitis C virus (HCV) and human immunodeficiency virus (HIV), HCV viraemia is increased. Because the HCV genotype 1 is associated with elevated viraemia, the increase in HCV viraemia observed and described in HIV+ patients could be attributed to the predominance of HCV genotype 1 in these patients. Therefore, the purpose of this study was to quantify HCV RNA in patients coinfected with HIV and HCV, according to the HCV genotype. The HCV genotype was thus determined in serum samples of 59 HIV+HCV+ patients and 51 HIV-HCV+ patients. HCV RNA was quantified using a branched DNA assay and the HCV genotype was determined using the "InnoLiPA" technique. The distribution of the HCV genotype was not significantly different in the two groups of patients, and there were even more patients infected by genotype 1 in the HIV-HCV+ group. The mean HCV viraemia of patients infected by HCV genotype 1 and by HCV genotype 3 was higher in patients coinfected by HIV than in HIV- patients (p < 10(-7) and p = 0.05, respectively). The increase in HCV viraemia observed in HIV+ patients was not the result of a specific distribution of HCV genotype in these patients. HIV infection was responsible for an increase in HCV viraemia irrespective of the HCV genotype.

Abnormal urinary coproporphyrin levels in patients infected by hepatitis C virus with or without human immunodeficiency virus. A study of 177 patients

OBJECTIVE

Many cases of porphyria cutanea tarda have been described in association with human immunodeficiency virus (HIV) infection in young individuals. The link between hepatitis C virus (HCV) and porphyria cutanea tarda is even stronger as more than 50% of patients who have this diagnosis in Italy, France, or Spain are also infected by HCV. To study the role of viral infections on the metabolism of porphyrins, we measured the urinary porphyrin levels in patients with HIV and HCV infections.

DESIGN

Survey; prospective study.

SETTING

University Hospital of Strasbourg, France.

PATIENTS

Sixty-one HIV-positive patients, 56 HCV-positive patients, 60 HIV- and HCV-positive patients, and 51 HIV- and HCV-negative control subjects were randomly selected. None had clinical signs of porphyria or a familial history of porphyria.

MAIN OUTCOME MEASURES

The porphyrin-excretion profile was determined by high-performance liquid chromatography on fresh urine samples. The HIV and HCV viremias were quantified in the serum by the branched DNA assay. Measures were planned before data collection began.

RESULTS

The porphyrin-excretion profile typical of porphyria cutanea tarda was found in only 1 of 177 patients. In the remaining 176 patients, the mean coproporphyrin level was significantly raised in HCV-positive patients and even higher in patients who were HIV- and HCV-positive. The coproporphyrin level was not correlated to the alanine aminotransferase level, the CD4+ cell count, or the HCV and HIV viremias.

CONCLUSIONS

In cases of infection with HIV, HCV, or both, the development of a porphyria cutanea tarda urinary profile is a rare event (0.56% in this study), but coproporphyrin excretion is increased. This could be related to hepatic changes induced by the viruses. Our results do not support the hypothesis of a direct viral effect on the porphyrin metabolism. Infection with HIV, HCV, or both may be a major triggering factor, but is not sufficient to induce porphyria.

Quantification of hepatitis C virus RNA in peripheral blood mononuclear cells: a comparison between patients chronically infected by HCV and patients coinfected by HIV

In patients chronically infected by hepatitis C virus (HCV), peripheral blood mononuclear cells (PBMCs) were shown to be targets for virus replication and in those coinfected with HIV, HCV viraemia was considerably increased. The purpose of this study was to quantify HCV RNA in PBMCs from 25 patients infected by HCV and from 25 patients coinfected by HCV and HIV. We used the branched DNA assay after extraction of total RNA on 5 x 10(6) cells to quantify HCV RNA, and the Inno LiPA assay to determine the HCV genotype. HCV RNA in PBMCs could be quantified in 8/25 patients in each group, but the HCV RNA concentration was very low in comparison with viraemia, since the highest result was 8.1 x 10(4) Eq genome/10(6) cells. In 10 ml of total blood, there was approximately 100 to 5,000 times less HCV RNA in PBMCs than in the plasma. It is therefore likely that PBMCs play only a minor part in the viral load present in the plasma. There was no preferential genotype associated with quantifiable HCV RNA in the PBMCs. In the case of HIV coinfection, there was no increase in the HCV-RNA concentration in PBMCs that could explain the increased viraemia observed in these patients. On the contrary, HCV RNA could not even be detected by RT-PCR in some of our coinfected patients.

Comparison of resection, liver transplantation and transcatheter oily chemoembolization in the treatment of hepatocellular carcinoma

BACKGROUND/AIMS

Resection and liver transplantation are currently considered as the most useful treatments for hepatocellular carcinoma. However, transcatheter oily chemoembolization may be favourably compared with these two surgical treatments in patients with anatomically operable tumors.

METHODS

Between 1985 and 1991, 122 patients with an Okuda stage I tumor were hospitalized in two French hospitals. Among these patients, 33 remained untreated, 42 were treated by transcatheter oily chemoembolization, 30 by resection and 17 by liver transplantation. The four groups were closely comparable except for age, the patients in the two surgical groups being significantly younger. Moreover, the frequency of pTNM II tumor was significantly higher in the resection group.

RESULTS

The 5-year probability of survival was close to 45% in each of the three treated groups and was significantly higher than in the untreated group (0% at 4 years, p < 0.0001). The probability of cancer recurrence and/or metastatic dissemination was lower after transcatheter oily chemoembolization than after surgery.

CONCLUSION

Thus, transcatheter oily chemoembolization seems comparable at 5 years with resection or transplantation for the treatment of resectable hepatocellular carcinoma.

The dopamine transporter protein gene (SLC6A3): primary linkage mapping and linkage studies in Tourette syndrome

The dopamine transporter, the molecule responsible for presynaptic reuptake of dopamine and a major site of action of psychostimulant drugs, including cocaine, is encoded by locus SLC6A3 (alias DAT1). The protein's actions and DAT's specific localization to dopaminergic neurons make it a candidate gene for several psychiatric illnesses. Alleles at this locus have been reported to be associated with cocaine-induced paranoia and attention deficit disorder. SLC6A3 has been mapped to distal chromosome 5p, using physical methods. Our goal was to place SLC6A3 in the genetic linkage map and to test for linkage to Tourette syndrome. Genetic linkage methods were used to place SLC6A3 in the genetic linkage map. Four extended pedigrees (one of which overlaps with CEPH) were typed. Linkage with Tourette syndrome (TS) was also examined. SLC6A3 showed close linkage with several markers previously mapped to distal chromosome 5p, including D5S11 (Zmax = 16.0, theta M = theta F = 0.03, results from four families) and D5S678 (Zmax = 7.84, theta M = theta F = 0, results from two families). Observed crossovers established that SLC6A3 is a distal marker close to D5S10 and D5S678, but these three distal markers could not be ordered. Linkage between TS and SLC6A3 could be excluded independently in two branches of a large kindred segregating TS; the lod score in a third family was also negative, but not significant. Cumulative results show a lod score of -6.2 at theta = 0 and of -3.9 at theta = 0.05 (dominant model, narrow disease definition). SLC6A3 thus maps to distal chromosome 5p by linkage analysis, in agreement with previous physical mapping data. A mutation at SLC6A3 is not causative for TS in the two large families that generated significant negative lod scores (if the parameters of our analyses were correct) and is unlikely to be causative in the family that generated a negative lod score that did not reach significance. These results do not exclude a role for the dopamine transporter in influencing risk for TS in combination with other loci.

[Hepatosplenic silicosis]

A case of hepatosplenic silicosis complicating a pulmonary silicosis is reported. Numerous calcified splenic nodules seen with conventional radiology, ultrasound or computed tomography, hepatic microcalcifications and "egg shell" abdominal lymph nodes best seen with computed tomography represent the radiologic signs. However, hepatosplenic silicosis can only be confirmed by pathological examination of liver biopsies showing birefringent particles within hyalinized nodules.

Differential expression of tyrosine hydroxylase and membrane dopamine transporter genes in subpopulations of dopaminergic neurons of the rat mesencephalon

Dopaminergic (DA) cells of the substantia nigra pars compacta (SNC) and the ventral tegmental area (VTA) display differences in their topography, biochemistry and susceptibility to pathological processes. Neuronal dopamine concentration is regulated in large part by tyrosine hydroxylase (TH), the rate-limiting enzyme of dopamine synthesis, and by the dopamine reuptake system. In the present study, TH protein, TH mRNA and dopamine membrane transporter (DAT) mRNA were quantified at cellular level in 4 arbitrary subregions of the rat ventral mesencephalon (lateral, middle, medial SNC and VTA), using in situ hybridization and immunoautoradiography. The distribution of labelling for TH protein and TH mRNA was almost superimposable and close to that of DAT mRNA in mesencephalic neurons. Lower values of cellular expression in TH protein, TH mRNA and DAT mRNA were observed in the lateral part of the SNC compared to the other subregions. TH and DAT expression were correlated in SNC but not in VTA. Indeed DA cells in this region expressed low levels of DAT mRNA in comparison to the middle and medial SNC. These results suggest a heterogeneity of DA metabolism among populations of mesencephalic cells. The relative lower expression of the DAT gene in VTA neurons suggests a less efficient dopamine reuptake capacity, which may partly account for the relative sparing of the mesolimbic system reported in Parkinson's disease and MPTP-treated animals.

Reduction in dopamine transporter mRNA after cessation of repeated cocaine administration

Male, Lewis rats were treated intravenously for 2 weeks with saline or cocaine using a dose and injection schedule that is similar to the doses and patterns of cocaine intake in self-administration studies. Ten days after cessation of treatment, dopamine transporter binding levels were decreased in the nucleus accumbens but not in the striatum. In situ hybridization studies revealed decreases in dopamine transporter mRNA that were restricted to cells of the interfascicular and caudal linear nuclei; these dopaminergic cell groups, found in the ventral tegmentum, project to the nucleus accumbens and other limbic areas. Other dopaminergic cell groups in midbrain which project mainly to other areas did not show a decrease in mRNA. These results indicate that gene expression can be altered many days after withdrawal from cocaine, and provide an example of transporter regulation by a change in gene expression.

Species differences in dopamine transporters: postmortem changes and glycosylation differences

The apparent molecular masses of photoaffinity-labeled dopamine transporters (DATs) from rat, human, dog, and primate kidney COS cells expressing the rat DAT1 cDNA differ. Sequences predicted from cDNA cloning reveal only one amino acid difference between the length of the rat and human DAT but one less site for potential N-linked glycosylation in the human DAT. Possible posttranslational and postmortem bases for species differences in DAT molecular mass were explored. Rat DAT proteins from striata subjected to approximately 5 h of postmortem delay modeled after the human postmortem delay process revealed small but consistent losses in apparent molecular mass and in cocaine analogue binding; the DAT molecular mass displayed no further losses for up to 30 h of model postmortem treatment. Degradative postmortem changes could thus contribute to molecular mass differences between rat and human DATs. Neuraminidase treatment reduced the apparent molecular mass of native rat DAT but not that of the rat DAT expressed in COS cells, suggesting that the sugars added to the DAT expressed in COS cells were different than those added to the rat brain striatal transporter. These differences could account for the somewhat higher Km values for expressed DAT cDNA in COS cells when compared with the wild-type striatal transporter. These results are in accord with the differences in number of predicted N-linked glycosylation sites between rat and human DATs and with cell-type specificity in transporter posttranslational processing.

Substance abuse vulnerability and D2 receptor genes

Dopamine systems are key to the actions of several substances. Inter-individual differences in genes encoding proteins involved in dopaminergic neurotransmission could plausibly explain some of the genetic bases for inter-individual differences in vulnerability to substance abuse. The restriction fragment length polymorphism (RFLP) markers TaqIA1 and B1 at the dopamine D2 receptor (DRD2) gene locus in Caucasians are associated with substance abuse behaviors. In most, but not all, studies of alcoholics and polysubstance abusers, these TaqIA1 and B1 gene markers are present more often in substance abusers than in control individuals. No study has identified substance abusers or controls by sampling randomly from the general population; allelic association findings could thus conceivably be confounded by RFLP differences based on ethnicity or other factors. However, meta-analyses of the data from controlled studies available to date are consistent with the proposal that DRD2 gene variants contribute to inter-individual differences in vulnerability to alcoholism and polysubstance abuse.

Fos family member changes in nucleus caudalis neurons after primary afferent stimulation: enhancement of fos B and c-fos

In situ hybridization using cDNAs complementary to specific regions of the mRNAs encoding four members of the FOS transcription factor gene family reveals modest levels of hybridization over superficial lamina of the nucleus caudalis of the spinal tract of the trigeminal in sections taken from unstimulated brains. Fos B expression is markedly and rapidly enhanced ipsilateral to electrical stimulation of the trigeminal ganglia. c-fos mRNA also changes; these differences contrast with the lack of significant changes in the low basal levels of expression of fra-1 and fra-2 mRNAs. The prominent change in fos B mRNA is mediated largely by an increase in the number of neurons that express hybridization densities above background after stimulation. This result, taken together with data on stimulation-induced changes in expression of preproenkephalin and other AP-1 transcription factors in wild-type animals and stimulation-induced changes in CAT activity in transgenic mice expressing portions of the proenkephalin promoter, is consistent with a role for the enhanced fos B expression in upregulation of expression of preproenkephalin in these neurons.

Dopamine transporter mRNA: dense expression in ventral midbrain neurons

Oligonucleotides and a full-length cDNA encoding a functional dopamine transporter (DAT1) hybridize to a 3.7 kb mRNA that is concentrated in mRNA prepared from midbrain and absent in specimens from cerebellum or cerebral cortex. In situ hybridization reveals substantial hybridization densities overlying neurons of the substantia nigra, pars compacta, and the parabrachialis pigmentosus region of the ventral tegmental area (VTA). Neurons in the linear and paranigral VTA regions display lower levels of expression. Preliminary studies in arcuate neurons suggest modest hybridization. Different dopaminergic cell groups display different levels of DAT1 dopamine transporter expression.

Expression of a single dopamine transporter cDNA can confer two cocaine binding sites

Radiolabeled cocaine analogs can bind to low and high affinity sites on striatal dopamine transporters (DAT). Recently, a cDNA encoding a rat brain dopamine transporter pDAT1 has been cloned. COS cells transfected with the pDAT1 in a eukaryotic expression vector express both a high (KD = 3.4 nM) and low affinity (KD = 163.6 nM) cocaine binding sites, suggesting that both sites are provided by a single gene product.

Cloning and expression of a cocaine-sensitive dopamine transporter complementary DNA

A rat dopamine (DA) transporter complementary DNA has been isolated with combined complementary DNA homology and expression approaches. The DA transporter is a 619-amino acid protein with 12 hydrophobic putative membrane-spanning domains and homology to the norepinephrine and gamma-aminobutyric acid transporters. The expressed complementary DNA confers transport of [3H]DA in Xenopus oocytes and in COS cells. Binding of the cocaine analog [3H]CFT ([3H]2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane) to transfected COS cell membranes yields a pharmacological profile similar to that in striatal membranes.

Endothelin receptor: a profoundly desensitizing receptor expressed in Xenopus oocytes

Xenopus oocyte expression studies can help to define the physiological properties of a receptor and can aid in receptor cloning. Expression of an endothelin receptor in oocytes injected with brain mRNA is inferred from depolarizations induced by several endothelin-related peptides. The response is abolished by intracellular EGTA injection but not in the absence of extracellular Ca2+. It is not present in non-injected oocytes, and reverses at a potential indicating that it is mediated by an increased Cl-1 conductance. Responses display striking, long-lasting desensitization. The expressed endothelin receptor thus displays properties characteristic of several receptors coupled to changes in phosphoinositide turnover, several of which have been successfully cloned using this response as a reporter.

Variations in normal electrocardiographic response to treadmill testing

Forty healthy young men at low risk for coronary artery disease underwent progressive maximal treadmill testing. Four bipolar electrocardiographic leads including CM5, CC5, inferior-superior Y, anterior-posterior Z, and a standard V5 were recorded and later computer-processed. Measurements included amplitudes of the Q, R, S, J junction and T wave, R-T and Q-S intervals and S-T segment slope. These variables are presented as the 10th, 50th (median) and 90th percentiles throughout the testing procedure to define reference values for the electrocardiographic response to maximal treadmill testing. The medians are presented graphically so that the exercise-induced changes can be visualized. In addition, the percent change of R wave amplitude in V5 compared with the supine pretest value is displayed for each subject during and after testing.