Dopa decarboxylase gene polymorphisms and attention deficit hyperactivity disorder (ADHD): no evidence for association in the Irish population

Dopa decarboxylase (DDC) is an enzyme which catalyses the decarboxylation of both dopa to dopamine and L-5 hydroxytryptophan to serotonin. Both catecholamines are major neurotransmitters of the mammalian nervous system. It has been suggested that genes involved in the dopaminergic system play a primary role in predisposing to attention deficit hyperactivity disorder (ADHD). In this study, the 4-bp insertion/deletion variant mapped to the first neuronally expressed exon 1 at the dopa decarboxylase gene and two microsatellite markers flanking the gene were investigated for possible association with ADHD. Using HHRR, we observed an increased transmission (though not significant) of the 4-bp insertion (allele 1) to ADHD cases (chi(2) = 2.72, P = 0.1, RR = 1.25). However marginally significant excess transmission of allele 10 (213 bp) of the 3' microsatellite D7S2422 ( approximately 0.75 cM distal to dopa decarboxylase gene) was found (chi(2) = 4.2, P = 0.04, RR=1.48). Interestingly, a haplotype containing both alleles is transmitted more frequently (chi(2)= 5, P = 0.025). Analysing data by the sex of transmitting parent showed a greater relative risk for paternal transmission of the 4-bp insertion allele and allele 10 of the D7S2422 (RR = 1.48 and 1.63 respectively). This provides preliminary evidence that this locus or a closely mapped DNA variant may be involved in the genetic susceptibility to ADHD. However, further studies are required to either confirm or refute these observations.

Nicotinic acetylcholine receptor alpha4 subunit gene polymorphism and attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a highly heritable, common psychiatric disorder that presents in childhood and that probably involves several genes. There are several lines of evidence suggesting that the nicotinic system may be functionally significant in ADHD: (a) nicotine promotes the release of dopamine and has been shown to improve attention in adults with ADHD, smokers and non-smokers; (b) ADHD is a significant risk factor for early initiation of cigarette smoking in children; (c) maternal cigarette smoking appears to be a risk factor for ADHD; (d) animal studies in rats and monkeys also suggest that nicotine may be involved in attentional systems and locomotor activity; and (e) a central nicotinic agonist, ABT-418, improves attention in both monkeys and ADHD adults. The current study examined the alpha 4 receptor, one of the sites of action of ABT-418. A known Cfol polymorphism within the nicotinic acetylcholine alpha 4 receptor gene, CHRNA4, was studied in 70 ADHD parent-proband trios from an ongoing sample collection of children aged 6-12 with ADHD, according to DSM-IV criteria. Children with known major medical or psychiatric conditions or mental retardation (IQ < 70) were excluded from the study. The Transmission Disequilibrium Test demonstrated no evidence that variation at the nicotinic acetylcholine alpha 4 receptor Cfol polymorphism influences susceptibility to ADHD (P > 0.35). The continuing sample collection will enable further study of other potential nicotinic system polymorphisms in ADHD in more powerful samples.

Familiality of symptom dimensions in schizophrenia

The division of schizophrenic symptoms into three core dimensions - psychomotor poverty, reality distortion, and disorganisation - is well established. When factor analytic studies have included affective symptoms they have identified two additional dimensions - manic and depressive. Whether these five dimensions represent underlying psychopathology of a genetic or environmental aetiology remains unclear. The aims of this study were to perform factor analysis of symptoms in a group of familial schizophrenic patients and to investigate the familiality of the symptom dimensions identified, and their relationship to clinical characteristics. Symptoms were recorded, using the Operational Criteria Checklist for Psychotic Illness, for 155 Caucasian subjects with an RDC diagnosis of schizophrenia, schizoaffective disorder, or psychosis of unknown origin, from 61 families multiply affected with schizophrenia. Factor analysis indicated five symptom dimensions: depressive, manic, reality distortion, disorganisation, and psychomotor poverty. The psychomotor poverty, disorganisation, and manic dimensions were shown to be familial. Psychomotor poverty, disorganisation, and reality distortion were all associated with deterioration from premorbid functioning and chronic course of the disorder. In addition, psychomotor poverty was significantly related to poor premorbid functioning, as well as to single marital status and unemployment at onset. Disorganisation was significantly related to single marital status and unemployment at onset. The familiality of the psychomotor poverty, disorganisation, and manic dimensions supports their use in the delineation of homogeneous subsets for genetic studies.

Vascular trauma induces rapid but transient mobilization of VEGFR2(+)AC133(+) endothelial precursor cells

Bone marrow (BM)-derived circulating endothelial precursor cells (CEPs) are thought to play a role in postnatal angiogenesis. Emerging evidence suggests that angiogenic stress of vascular trauma may induce mobilization of CEPs to the peripheral circulation. In this regard, we studied the kinetics of CEP mobilization in two groups of patients who experienced acute vascular insult secondary to burns or coronary artery bypass grafting (CABG). In both burn and CABG patients, there was a consistent, rapid increase in the number of CEPs, determined by their surface expression pattern of vascular endothelial growth factor receptor 2 (VEGFR2), vascular endothelial cadherin (VE-cadherin), and AC133. Within the first 6 to 12 hours after injury, the percentage of CEPs in the peripheral blood of burn or CABG patients increased almost 50-fold, returning to basal levels within 48 to 72 hours. Mobilized cells also formed late-outgrowth endothelial colonies (CFU-ECs) in culture, indicating that a small, but significant, number of circulating endothelial cells were BM-derived CEPs. In parallel to the mobilization of CEPs, there was also a rapid elevation of VEGF plasma levels. Maximum VEGF levels were detected within 6 to 12 hours of vascular trauma and decreased to baseline levels after 48 to 72 hours. Acute elevation of VEGF in the mice plasma resulted in a similar kinetics of mobilization of VEGFR2(+) cells. On the basis of these results, we propose that vascular trauma may induce release of chemokines, such as VEGF, that promotes rapid mobilization of CEPs to the peripheral circulation. Strategies to improve the mobilization and incorporation of CEPs may contribute to the acceleration of vascularization of the injured vascular tissue.

From the Central Valley to the Sierras: Air Med Team

Effective treatment of the critically ill or injured patient and rapid transport to definitive care have been the goals of the air medical industry since its inception. For the past 6 years, Air Med Team (AMT), a service of Doctors Medical Center (DMC) in Modesto, Calif., has delivered timely and often lifesaving care to the largely rural area of the Central Valley and the Sierras. AMT was established in an effort to complete the spectrum of health care services offered by DMC and ensure easy access to the critical care services available at this facility. Established in February 1994, AMT strives to provide a safe and efficient approach to patient care in the prehospital environment. More than 4200 accident-free missions and 1900 patient transports have been completed since our first activation on March 14, 1994.

Relationships of perceived stress to coping, attachment and social support among HIV-positive persons

The purpose of this study was to examine the relationships of coping, attachment style and perceived social support to perceived stress within a sample of HIV-positive persons. Participants were 147 HIV-positive persons (80 men and 67 women). Multiple regression analysis was used to examine the relationships of the demographic variables, AIDS status, three coping styles, three attachment styles and perceived quality of general social support with total score on the Perceived Stress Scale (PSS). PSS score was significantly associated with less income, greater use of behavioural and emotional disengagement in coping with HIV/AIDS, and less secure and more anxious attachment styles. These results indicate that HIV-positive persons who experience the greatest stress in their daily lives are those with lower incomes, those who disengage behaviourally/emotionally in coping with their illness, and those who approach their interpersonal relationships in a less secure or more anxious style.

Biosynthesis of tetrahydroanthraquinones in fungi

The tetrahydroanthraquinones (1S,3S)-austrocortilutein (4) and (1S,3S)-austrocortirubin (7) are octaketides formed in the fruit bodies of the fungus Dermocybe splendida via the gentiobioside 2 of the dihydroanthracenone (S)-torosachrysone (1).

Autocrine stimulation of VEGFR-2 activates human leukemic cell growth and migration

Emerging data suggest that VEGF receptors are expressed by endothelial cells as well as hematopoietic stem cells. Therefore, we hypothesized that functional VEGF receptors may also be expressed in malignant counterparts of hematopoietic stem cells such as leukemias. We demonstrate that certain leukemias not only produce VEGF but also express functional VEGFR-2 in vivo and in vitro, resulting in the generation of an autocrine loop that may support leukemic cell survival and proliferation. Approximately 50% of freshly isolated leukemias expressed mRNA and protein for VEGFR-2. VEGF(165) induced phosphorylation of VEGFR-2 and increased proliferation of leukemic cells, demonstrating these receptors were functional. VEGF(165) also induced the expression of MMP-9 by leukemic cells and promoted their migration through reconstituted basement membrane. The neutralizing mAb IMC-1C11, specific to human VEGFR-2, inhibited leukemic cell survival in vitro and blocked VEGF(165)-mediated proliferation of leukemic cells and VEGF-induced leukemic cell migration. Xenotransplantation of primary leukemias and leukemic cell lines into immunocompromised nonobese diabetic mice resulted in significant elevation of human, but not murine, VEGF in plasma and death of inoculated mice within 3 weeks. Injection of IMC-1C11 inhibited proliferation of xenotransplanted human leukemias and significantly increased the survival of inoculated mice. Interruption of signaling by VEGFRs, particularly VEGFR-2, may provide a novel strategy for inhibiting leukemic cell proliferation.

Agony and ecstasy: a review of MDMA effects and toxicity

BACKGROUND

Ecstasy is a recreational drug with an anecdotal reputation for safety. However, reports of adverse effects and fatalities have increased in the medical and popular press.

METHOD

Literature search and review.

RESULTS

Acute Ecstasy toxicity does not appear to be due to overdose and cannot be solely attributed to the nature of the usual ambient environment. Adverse effects include hyperthermia, seizures, cardiac arrhythmias, hepatotoxicity, hyponatraemia and many psychiatric disorders. Ecstasy causes serotonergic neurotoxicity in the brains of animals at doses close to those used by humans, but its long-term effect on the human brain is unknown.

CONCLUSION

Ecstasy toxicity should be considered in the differential diagnosis of a variety of medical and psychiatric conditions. Given its popularity, both the acute and the potential long-term effects are a cause for concern.

Genetic characterization of type 2 porcine circovirus (PCV-2) from pigs with postweaning multisystemic wasting syndrome in different geographic regions of North America and development of a differential PCR-restriction fragment length polymorphism assay to detect and differentiate between infections with PCV-1 and PCV-2

Postweaning multisystemic wasting syndrome (PMWS) is an emerging disease in swine. Increasing evidence indicates that a variant strain of porcine circovirus (PCV), designated type 2 PCV (PCV-2), is responsible for PMWS. To determine the extent of genetic heterogeneity of PCV-2 isolates, the complete genomes of six PCV-2 isolates from different regions of North America were amplified by PCR and sequenced. Sequence and phylogenetic analyses confirmed that two distinct genotypes of PCV exist: nonpathogenic genotype PCV-1 and PMWS-associated genotype PCV-2. However, within the PCV-2 genotype, several minor branches that have been identified appear to be associated with geographic origins. The genomic sequences of two French PCV-2 isolates diverge the most from those of other PCV-2 isolates and form a distinct branch. Other minor but distinguishable branches have also been identified for a Taiwan PCV-2 isolate and two of the Canadian PCV-2 isolates. All the U.S. PCV-2 isolates are closely related, but the Canadian isolates vary, to some extent, in their genomic sequences. The data from this study indicate that although the genome of PCV-2 is generally stable among different isolates, PCV-2 isolates from different geographic regions vary in their genomic sequences. This variation may have important implications for PCV-2 diagnosis and research. On the basis of genetic analyses of available PCV strains, a universal PCR-restriction fragment length polymorphism (PCR-RFLP) assay was developed to detect and differentiate between infections with PCV-1 and PCV-2. This PCR-RFLP assay should be useful for studying the pathogenesis of PCV-2, for detecting PCV-2 infection in pigs from different geographic regions, and for screening donor pigs for use in xenotransplantation.

No association of the dopamine DRD4 receptor (DRD4) gene polymorphism with attention deficit hyperactivity disorder (ADHD) in the Irish population

Attention deficit hyperactivity disorder (ADHD) is one of the most prevalent childhood-onset syndromes affecting 3%-6% of school-age children worldwide. Although the biological basis of ADHD is unknown, a dopaminergic abnormality has long been suggested. The dopamine D4 receptor gene (DRD4) has been mapped to chromosome 11p15.5 and has been implicated in predisposition to ADHD. Several independent genetic association studies have demonstrated increased frequency of the DRD4 7-repeat allele in ADHD cases compared with controls or excess transmission of the 7-repeat allele from parents to affected offspring. However, there have also been few negative studies. In this study we investigated 78 ADHD parent proband trios and 21 parent proband pairs for the transmission of the DRD4 alleles in HHRR and case control design. We found no significant differences in the frequency of the DRD4 alleles transmitted or not transmitted to ADHD cases from their parents nor when comparing case allele frequencies to ethnically matched controls. Therefore, it is unlikely that the DRD4 7-repeat allele is associated with ADHD in the Irish population.

No association between catechol-O-methyltransferase (COMT) gene polymorphism and attention deficit hyperactivity disorder (ADHD) in an Irish sample

Pharmacological and biochemical studies have indicated that imbalances in dopaminergic transmission may contribute to the aetiology of attention deficit hyperactivity disorder (ADHD). The enzyme catechol-O-methyltransferase (COMT) plays a key role in the degradation of catecholamines such as dopamine, L-DOPA, adrenaline, and noradrenaline and therefore could be considered as a candidate locus for ADHD susceptibility. We hypothesised that a proportion of the genetic susceptibility to ADHD may be a consequence of dopamine depletion in the synapses due to high-level activity of the COMT gene (allele 1). Using the haplotype-based haplotype relative risk method and 94 affected children and their parents genotyped for COMT alleles, we found no significant differences in the frequency of the transmitted and nontransmitted alleles to ADHD cases from their parents. The absence of association between COMT alleles and ADHD indicated that this locus does not play a significant role or at least a role independent of other genes, in predisposing to ADHD in the Irish population.

[Lack of gender effect on familial schizophrenia. A Brazilian study]

Epidemiological studies on schizophrenia have showed different age at onset between gender, in which male schizophrenics present symptoms earlier than females. However this gender effect is not observed within familial schizophrenia. The present study investigates the age at onset in 31 RDC-schizophrenics from 13 Brazilian families. No differences in age at onset were found between gender, confirming previous studies in other populations. This result may indicate genetic influences on age at onset in a subgroup of patients affected by schizophrenia and can be explored by molecular genetic studies.

Intra-abdominal needles: an enigma (a report of two cases)

Ingested sharp metallic bodies perforate the gut surprisingly rarely. Perforation and migration of such a foreign body may be silent. Patients may present with unrelated symptoms and the discovery of foreign body on radiological examination of the abdomen may come as a surprise. History of ingestion is usually difficult to obtain. Foreign bodies after perforation have been reported to migrate to almost any intraabdominal or rarely to even extra-abdominal sites. Migration to the liver, mesentery or the anterior abdominal wall, however, is extremely rare. We report two cases of young women with two ingested needles in each which perforated silently and in one case migrated to the liver and the anterior abdominal wall while in the other they migrated to the mesentery of the small intestine and the anterior abdominal wall.

Outer-membrane proteins pattern and detection of beta-lactamases in clinical isolates of imipenem-resistant Acinetobacter baumannii from Brazil

In order to compare imipenem-sensitive and -resistant Acinetobacter baumannii strains isolated from three patients, ribotyping, plasmid, beta-lactamase detection and outer-membrane analysis were performed. Ribotyping and the use of a beta-lactam during the period when the strains were isolated suggested that they had a common origin and that resistance occurred in vivo. Outer membrane analysis showed no difference between susceptible and resistant strains with the exception of an A2 imipenem-resistant strain that lost a protein band of 31-36 kDa. Beta-lactamases were detected using isoelectric focusing in all strains (pI of 7.4). In addition, two beta-lactamases (pI of 5.9 and 6.7) were found in imipenem-resistant isolates. The double-disc technique demonstrated the presence of a beta-lactamase capable of imipenem inactivation in resistant strains. Plasmid analysis showed that all susceptible strains had the same pattern, one resistant strain did not have any plasmid, one had the same plasmid pattern of its susceptible pair and only one had a different pattern when compared with its susceptible pair.

Presenilin 1 and alpha-1-antichymotrypsin polymorphisms in Down syndrome: no effect on the presence of dementia

As people with Down syndrome (DS) age, they are at greater risk for Alzheimer disease (AD) than the general population. It has been suggested that polymorphisms at the genes for presenilin-1 (PS-1) and alpha-1-antichymotrypsin (ACT) confer an increased risk for AD in the general population, and therefore potentially to AD in people with DS. We obtained DNA from 231 individuals with DS and 233 population controls. People with DS were evaluated for dementia. Allele frequencies at PS-1 and ACT polymorphisms in people with DS were compared to those in age-matched controls. There were no frequency differences between the control sample and DS sample for PS-1 or ACT alleles or genotypes. Similarly, there were no differences in allele frequencies between the demented and age-matched non-demented DS samples. However a higher frequency of PS-1 heterozygotes in the demented DS group was noted. We conclude that unlike the general population, neither PS-1 nor ACT polymorphisms appear to have a similar detrimental effect on dementia in DS. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:616-620, 1999.

Age at onset of dementia and age of menopause in women with Down's syndrome

Menstrual status and the age of menopause were investigated in 143 Irish females with Down's syndrome (DS). The average age of menopause in 42 subjects (44.7 years) was younger than in the general population. The age at onset of dementia correlated with the age of menopause. This finding may be a manifestation of accelerated ageing in DS or point to oestrogen deficiency being an independent risk factor for the development of Alzheimer's dementia in DS. The implications of this finding for possible treatments are discussed.

Linkage studies of bipolar disorder with chromosome 18 markers

Evidence consistent with the existence of genetic linkage between bipolar disorder and three regions on chromosome 18, the pericentromeric region, 18q21, and 18q22-q23 have been reported. Some analyses indicated greater evidence for linkage in pedigrees in which paternal transmission of disease occurs. We have undertaken linkage analyses using 12 highly polymorphic markers spanning these three regions of interest in a sample of 48 U.K. bipolar pedigrees. The sample comprises predominantly nuclear families and includes 118 subjects with Diagnostic and Statistical Manual of Mental Disorders (DSM IV) bipolar I disorder and 147 subjects with broadly defined phenotype. Our data do not provide support for linkage using either parametric or nonparametric analyses. Evidence for linkage was not significantly increased by analyses that allowed for heterogeneity nor by analysing the subset of pedigrees consistent with paternal transmission.