Estimating the prevalence of problem gambling among older adults in Singapore

This study examined the prevalence rates of problem gambling among older adults in Singapore. A stratified sampling method was used to select the nationally representative sample of 3010 older adults aged 55 years and above. The survey participants were of varying ethnicities living in the community, including Chinese, Malay, and Indian (and others). A structured questionnaire, including the Canadian Problem Gambling Index, gambling attitudes and behaviors, and demographic information was administered face-to-face at participants' homes, using one of the four language versions preferred by the participants. Among those who had gambled lifetime, 69.7% (or weighted population = 39.2%) gambled in the past 12 months and 2.2% (or weighted population = .9%) met the problem gambling criteria. Individuals with problem gambling were likely to have started gambling at an younger age and to have gambled in activities characterized by continuity and no set money limits. Future research should examine changes in gambling behaviors of older adults over time in non-Western societies.     

Rapid size dependent deletion of foreign gene sequences inserted into attenuated HIV-1 upon infection in vivo: implications for vaccine development

Live attenuated HIV vaccines offer a means to introduce exogenous sequences into the viral genome to target the virus elimination in vivo. Foreign genes inserted into the nef region of HIV-1 NL4-3 were found to be rapidly deleted following virus infection and/or replication, in a size dependent manner, in the human fetal Thymus/Liver implants of severe combined immunodeficient mouse (SCID-hu) model. When the murine heat stable antigen (HSA) of 283 bp was substituted into HIV-1 nef region, the viral loads in vivo were comparable to the negative control nef attenuated HIV-1, and the reporter HSA gene was not deleted upon infection. However, the murine Thy1.2 gene (505 bp) substituted into the nef attenuated HIV-1, upon infection and replication, deleted 441 bp in vitro and 437 bp in vivo, of the inserted Thy1.2 gene. When the enhanced green fluorescence protein (eGFP) gene (720 bp) was substituted for nef, virus replication was aborted in vivo in the Thy/Liv implants, as seen by the background levels of viral loads, comparable to mock infected implants, and the eGFP gene was deleted. When the herpes simplex virus thymidine kinase gene, HSV-TK (1.15 kbp), or HSA gene, was substituted into the viral vpr gene, TK but not HSA gene was deleted, upon infection in vitro. Moreover, NL-TKI reporter virus with both intact nef and vpr genes shows deletion of TK gene both in vitro and in vivo. Excision of foreign genes occurred within the exogenous segments but not in the viral own regions. These results suggest that larger "suicide" genes introduced via HIV-1 can be deleted upon infection. However, smaller size nucleotide sequences or genes (approximately 300 bp) inserted in place of viral nef or vpr gene may be used to target the virus or its components, for attack and elimination in vivo, and thus have implications for the development of live attenuated HIV vaccines.     

Implantation of endoprostheses in aortocoronary bypass. Preliminary experience at the Thoraxcenter of Rotterdam

An intraluminal stent was implanted in 5 patients after dilatation of an aorto-coronary venous graft. In the first 4 patients the procedure was motivated by restenosis after angioplasty. In the 5th patient the stent was implanted as a first-line measure in a case of dilated venous bypass stenosis. Stent implantation carries a risk of thrombosis and requires effective anticoagulation. Thus, one of our patients had to be reoperated upon for prosthetic thrombosis facilitated by the withdrawal of anticoagulants owing to a gastrointestinal haemorrhage. After a 3-month follow-up, the results seem to be encouraging in spite of a case of restenosis located at the proximal end of the tutor. However, more time will be needed to determine precisely the effectiveness of stents in the prevention of restenosis after venous graft dilatation.     

Response to Diazepam in Sons of Alcoholics

Alcohol exerts several of its actions via the chloride channel associated with the central GABA-benzodiazepine receptor complex. To explore a possible role for this receptor complex in risk for alcoholism, and to determine whether risk for alcoholism is associated with risk for benzodiazepine abuse, the authors administered intravenous diazepam to 18 sons of male alcoholics (SOAs) and 18 control subjects. Four logarithmically increasing doses of diazepam and matched volumes of placebo were given in randomized order on separate days about 1 week apart. SOAs were significantly more likely than controls to report euphoric responses to diazepam. At some diazepam doses, SOAs were more likely to report feeling "high" and "intoxicated." SOAs and controls did not differ in feeling "drugged." SOAs and controls may differ in expectations regarding the subjective effects of drugs and/or in the function of the central GABA-benzodiazepine receptor complex. These findings also add further evidence for increased pleasurable effects, and thus possibly increased risk for benzodiazepine abuse, in a subgroup of SOAs.     

Ventricular fibrillation causes sudden death in Southeast Asian immigrants

Young, male, Southeast Asian immigrants living in the United States have a high incidence of unexplained, sudden, nocturnal death. We report the cases of three patients, two Laotians and one Filipino, who were resuscitated and subsequently studied extensively. Each patient was having ventricular fibrillation when first examined by paramedics outside the hospital, and episodes of fibrillation recurred in the early hospital course. Clinical evaluation found no significant coronary atherosclerosis or structural cardiac disease. One patient is asymptomatic after 2 years; the second patient died suddenly at 4 months; and the third is asymptomatic but had inducible ventricular tachycardia on electrophysiologic testing 6 months after resuscitation. The mechanism of sudden death in young Southeast Asian men appears to be ventricular fibrillation. The cause of the arrhythmia is unclear, although in our patients the arrhythmia was not an isolated event; underlying predispositions to further cardiac arrest persisted.     

Alcohol Self-Administration: Further Examination of the Role of Dopamine Receptors in the Nucleus Accumbens

One of the functions of the mesolimbic dopamine (DA) system is to regulate the process of reinforcement, a process that is thought to influence drug self-administration. This study tested the effects of centrally administered DA receptor ligands on ethanol self-administration behavior. Long-Evans rats were trained to lever press on a fixed-ratio 4 schedule of ethanol (10% v/v) reinforcement. DA agonists and antagonists were then bilaterally microinjected (0.5 μ/side) into the nucleus accumbens (N Acc) 10-min before sessions to test for effects on the onset, maintenance, and termination of ethanol self-administration. Infusions of the D₁-like agonist SKF 38393 (0.03 to 3.0 μg) produced no effect on ethanol self-administration. The D₁-like antagonist SCH 23390 (0.5 to 2.0 μg) reduced total responding by decreasing the time course of self-administration without altering response rate. The D₂-like agonist quinpirole produced a biphasic effect on self-administration. Quinpirole (1.0 μg) increased total responses and response rate, whereas higher doses (4.0 to 10.0 μg) decreased total responding as a result of early termination. The D₂-like antagonist raclopride (0.1 to 1.0 μg) reduced total responding by decreasing time course and response rate. Co-administration of either SKF 38393 or SCH 23390 with quinpirole prevented the behavioral effects observed with the low doses of quinpirole. Thus, in the N ACC either increased activation of D₁-like receptors or their blockade can affect the expression of the behavioral effects of the D₂-like agonist. This suggests that some intermediate level of D₁ activation is required to observe the D₂ effect. The decreases in total responding produced by raclopride were enhanced by co-administration of SKF 38393, but not altered by SCH 23390, thus suggesting that D₁-like and D₂-like receptors in the N Acc interact in the regulation of ethanol self-administration in a manner similar to their interactive regulation of other behaviors.     

Evidence for a physiological role for oxytocin in the control of prolactin secretion

The presence of oxytocin (OT) in neuronal elements of the external layer of the median eminence and in hypophysial portal plasma suggests a role for the peptide in the control of anterior pituitary function. We have reported previously that OT stimulates PRL release in vitro; therefore, we attempted to establish evidence for a physiological PRL-releasing role for OT. Plasma OT levels rose significantly just before the PRL surges occurring during a suckling stimulus in lactating rats (10 min after pup reinstatement vs. 15 min for PRL) and 48 h after estrogen injection in ovariectomized (OVX) rats (at 1200 h vs. 1300 h). Dispersed anterior pituitary cells harvested from lactating female rats and OVX estrogen-primed rats released PRL in a specific, significant, and dose-related fashion when perifused in vitro with incubation medium containing 10(-7)-10(-9) M OT, doses similar to levels found previously in hypophysial portal plasma. Infusion of antiserum specific for OT into lactating females before pup reinstatement and into estrogen-primed OVX rats 2 h before the expected release of endogenous OT delayed and significantly reduced subsequent PRL surges compared to levels in saline-or normal rabbit serum-infused rats; however, PRL release was not completely abolished. These data indicate that OT plays a physiological role in the hypothalamic control of PRL secretion and further suggest the importance of multiple factors in coordinated regulation of PRL release.