Reduced visuospatial performance in children with the D2 dopamine receptor A1 allele

Previous studies suggest a reduced dopaminergic function in subjects with the A1 (minor) allele of the D2 dopamine receptor (DRD2) gene. To explore influences on visuospatial ability as a function of the DRD2 gene, 182 alcohol- and other drug-naive sons (age 10–14) of active alcoholic, recovered alcoholic, and nonalcoholic fathers were administered a visuospatial task (Benton's Judgment of Line Orientation Test) which makes minimal motoric/verbal demands. Visuospatial scores were lower for boys with the A1 allele and for sons of active alcoholics. A1-allele boys made more errors than A2 boys on all 11 of the template lines, with the effect being largest for the rightmost presentations. In contrast, the effect of family history for alcoholism was strongest on both right and left midquadrant presentations. Moreover, separate analyses of the two types of errors produced allele but not family history of alcoholism effects when the two lines were misjudged as farther apart than they actually were and family history but not allele effects where the two lines were misjudged as closer together. These results suggest that polymorphism of the DRD2 gene and family history of alcoholism are dissociable determinants of visuospatial ability and that visuospatial defects previously observed in alcoholics may, in part, be antecedent to their drinking behavior.     

Comparison of leukocyte count and function in smoking and nonsmoking young men.

Leukocyte function and other hematological measurements were tested in 14 smoking and 13 nonsmoking young men free of intercurrent or chronic diseases. Leukocyte chemotaxis was depressed in smoking subjects when compared to the same subjects abstaining from cigarettes or to the nonsmokers. Smoking did not affect the whole blood bactericidal capacity of leukocytes and serum for Staphyloccus aureus or Klebsiella pneumoniae. Total leukocyte counts, hematocritis, and monocyte counts were higher in the smoking subjects when compared to the nonsmokers.     

A quantitative analysis of the slow component of delayed rectification in frog atrium

1. The slow component of delayed rectification in the atrial muscle membrane of Rana ridibunda has been analysed quantitatively using a voltage-clamp technique.2. It is shown that the current is proportional to a variable which obeys first-order kinetics. At negative potentials the time constant of this process is very long (tau = 3 sec at -55 mV) but it becomes faster at positive potentials (tau = 1.85 sec at +25 mV).3. In the steady state the degree of activation is a sigmoid function of potential. The activation threshold varies substantially between preparations but is usually negative to -30 mV.4. The instantaneous current-voltage relation is nearly linear and its reversal potential most frequently lies between zero and -30 mV.5. The properties of this current system resemble those of the current system i(x2) found in mammalian Purkinje fibres.     

Cellular content of amniotic fluid as predictor of central nervous system malformations.

Prospective observations on 442 consecutive samples have confirmed that pregnancies with CNS malformations are regularly associated with an abnormal cellular content of amniotic fluid. A crude semiquantitative test of the cell content can give valuable clinical information in relation to borderline amniotic fluid alpha-fetoprotein values, and help to detect false positive AFP's.     

Chronic amitriptyline administration increases serotonin transporter binding sites in the hippocampus of aged rats

The effects of ageing and of chronic antidepressant treatment upon 5-HT transporter sites ([3H]paroxetine binding) in the rat hippocampus was examined. [3H]paroxetine binding to transporter sites was decreased with ageing in the hippocampus of control rats (38% decrease in dentate gyrus and CA4). Amitriptyline (10 mg/kg, i.p.) had no significant effect on [3H]paroxetine binding in 10 months old rats, but increased binding sites in 24 months rats in all hippocampal subregions (greatest increase of 109% in CA1 compared to saline controls). These data indicate an age-related decrease in hippocampal serotonin transporter sites and upregulation of these sites following 10 weeks of amitriptyline. The observed increase in transporter sites following amitriptyline may contribute to the general lower effectiveness of tricyclic antidepressants with ageing.     

Cardiac cell membrane repolarization is required for onset of mechanical restitution in papillary muscle

In 10 voltage clamped ferret papillary muscles at 37 degrees C (single sucrose gap), the duration of resting (diastolic, holding) potential was varied in order to define the mechanical restitution process. Following a period of steady state voltage clamp depolarizations to +20 mV, a single test depolarization clamp of 200 or 500 ms duration was introduced. Then, the following period at resting (holding) potential was varied. All the mechanical restitution curves for the 500 ms clamps were delayed by 300 ms compared with the 200 ms clamps. When mechanical restitution was plotted as the relationship between contractile force and test electrical diastolic interval, all processes started from zero interval (i.e. the time of repolarization). Variation of diastolic holding potential between -70 mV and -40 mV did not affect the starting time, but the final force values at full restitution were approached faster and were higher for -70 mV than for -40 mV. There was an inverse relationship between force and second inward current during mechanical restitution after an initial phase of restitution of current. Mechanical restitution is postulated to be due to passage of contractile calcium with time from an uptake to a release compartment within the sarcoplasmic reticulum. Thus the rise of contractile force with increasing test cycle duration should have been independent of whether a 200 or 500 ms depolarization was used. In order to accommodate the discrepancy, we postulate either that (1) sarcoplasmic reticulum calcium release channels require sarcolemmal repolarization to begin to be reactivated or (2) that trigger calcium (calcium induced calcium release from the sarcoplasmic reticulum) is derived from the sarcolemma.     

Ethics in the trenches

The increasing understanding of stem cell biology has opened up the possibility of using cell transplantation to treat a large variety of diseases. The medical need to identify optimal therapies is being challenged, however, by some members of society who seek to impose on this scientific quest their views-generally associated with particular religious beliefs-of what constitutes allowable research. This conflict mirrors earlier battles, extending over 150 years, between those implementing inoculation and vaccination to protect against smallpox and those who felt this to be unethical for religious reasons. For the many individuals who might benefit from the potential of stem cell medicine, such prolonged debate is unacceptable. In this review, conflicts in this debate are examined by holding opponents of embryonic stem cell (ESC) research to the standards applied to the science. The challenge of identifying optimal cells for tissue repair is juxtaposed with misrepresentations of stem cell science by those opposed to ESC research. Absolutist views on ethics are juxtaposed with examples of the bad science and unethical acts that occur when dogmatic religious filters and definitions of human-ness are forced upon scientific discussions. Finally, after considering how opponents of ESC research may, ironically, enhance commercial demand for cells derived from fetuses aborted for personal reasons of the mother, 10 proposals are offered that would-if followed by all participants in this debate-produce more ethically balanced discussions and a more comprehensive body of data from which evidence-based conclusions can be drawn.     

Relationship of the quality and quantity of circulating anti-BSA antibodies to the severity of glomerulonephritis in rats with chronic serum sickness.

Chronic serum sickness glomerulonephritis, induced in hyperimmunized rats by daily intravenous administration of bovine serum albumin, occurs in three stages, mild, moderate and severe, with abrupt onsets and distinctive features of kidney pathophysiology and immunopathology. We have studied the relationship between circulating anti-BSA antibodies and the severity of glomerulonephritis at each stage. The total amount of antibodies declined gradually during the course of disease, to low concentrations in the most severe stage of kidney inflammation. High levels of immune complexes were present in the circulation while precipitating antibodies were maintained, and rats remained in the mill stage of disease, exhibiting no abnormalities of kidney function and only mesangial immunopathology. The start of the moderate stage of chronic serum sickness, identified by proteinuria and the accumulation of immune deposits along the glomerular basement membrane, was associated with the disappearance of precipitating antibodies from circulation. With the onset of the severe stage of disease, marked by depressed glomerular filtration and sodium excretion, circulating antibodies of high affinity were no longer detected and circulating immune complex levels were only marginally elevated above normal. The experiments reported here demonstrate that, in chronic serum sickness glomerulonephritis of rats, transitions from one stage of kidney disease to another can be inferred from changes in the population of circulating antibodies. Kidney histopathology, therefore, can be predicted reliably from serological data alone.