Bovine leukosis III. Relationship between lymphocytosis and DNA synthetic lymphocytes

The relationship between lymphocytosis and cell counts of lymophocytes synthesizing DNA in peripheral blood of 321 mature cows from two leukosis herds and a control herd and 11 cows with leukotic tumors was investigated. Only data from 20 control herd and 109 leukosis herd animals which remained persistently in either negative or suspect or positive hematological class on repeated bleedings were utilized. In the leukotic cattle these studies were limited to the terminal stages of the disease.A positive correlation was noted between the number of DNA synthesizing lymphocytes and lymphocytosis. Corresponding increases in peripheral blood lymphocytes and in the numbers of DNA synthesizing lymphocytes of leukotic cattle and animals of leukosis herds was attributed to impaired lymphocytopoiesis. The evaluation of the control herd and of the leukosis herds was not clear-cut on the basis of lymphocyte counts alone, although the differences were more clearly defined when the data from hematological studies and estimation of DNA synthesizing lymphocytes were evaluated. The G?ttingen bovine leukosis key classification in conjunction with the estimation of DNA synthesizing cells was found to be a reliable procedure for the early recognition of the leukosis herds but not leukotic individuals.     

Frequency-dependent sexual selection among wild-type strains ofDrosophila melanogaster

Frequency-dependent sexual selection was studied using three geographically isolated strains ofDrosophila melanogaster. The Oregon-R and Canton-Special wild-type strains were essentially homogeneous, having been maintained in laboratories since 1925; the wild Macomb strain was relatively genetically heterogeneous, having been collected in September 1972, immediately prior to this investigation. All possible double combinations of the three strains were placed in separate chambers of a modified Elens-Wattiaux observation apparatus at ratios of 520, 1212, and 205. Allowing 2 hr observation time for each chamber, data were collected to detect mating preference between these strains. There was no sexual isolation between the strains. However, frequency dependence, where rare males have a definite mating advantage in a population, was exhibited by the strains studied. Sexual vigor appeared to be a factor when the heterogeneous Macomb strain was mated to either of the two homogeneous strains in equal numbers.     

Bovine leukosis. II. Comparison of hematological classification with DNA synthesis between herds

Blood samples of 126 mature cows with "persistent" hematological status from two leukosis herds and a leukosis free control herd were collected for determining hematological status and estimation of replicating lymphocytes. To quantitate the number of DNA synthesizing cells, the blood was incubated with tritiated thymidine in vitro followed by autoradiography. Classification of animals according to lymphocytosis status did not reveal clearly whether or not a difference existed between the two leukosis herds. The estimation of DNA synthesizing lymphocyte counts showed that the animals from the two leukosis herds did not differ from each other while differing significantly from control herd animals. The study suggests that the similarities between the two leukosis herds, while ambiguous on lymphocyte counts alone, become clear when DNA synthesizing cell counts are compared. Thus the animals of the two leukosis herds belonged to the same "leukosis" population.     

Generalizability and durability of treatment effects in an intervention program for coronary-prone (type A) managers

To test the reliability and durability of positive treatment effects obtained in a type A intervention project for healthy managers, the analysis was extended to data available from a third treatment group (a special behavior therapy group for participants eliminated from the main sample because of manifestations of clinical CHD) and to measures obtained 6 months following the end of treatment. Immediately after treatment all three groups showed a similar pattern of improvement, although the two behavior therapy groups did show a greater decrease in serum cholesterol levels. Six months after treatment the sample as a whole showed good maintenance of treatment effects, but the differences between groups had become somewhat sharper, with the special behavior therapy group faring best, the regular behavior therapy group intermediate, and the psychotherapy group worst. The logical consistency of these findings increases our confidence in the initial treatment results, as well as permitting cautious optimism concerning the possibility of developing effective intervention programs for coronary-prone (type A) behavior.     

A high-fat meal impairs muscle vasodilatation response to mental stress in humans with Glu27 β<Subscript>2</Subscript>-adrenoceptor polymorphism

Background  

Forearm blood flow responses during mental stress are greater in individuals homozygous for the Glu27 allele. A high-fat meal is associated with impaired endothelium-dependent dilatation. We investigated the impact of high-fat ingestion on the muscle vasodilatory responses during mental stress in individuals with the Glu27 allele and those with the Gln27 allele of the β₂-adrenoceptor gene.     

Denny-Brown's views on the pathophysiology of dystonia.

We review Denny-Brown's hypotheses on the mechanisms underlying motor behavior and his views on how dysfunction in these mechanisms can result in dystonia. His formulations were based upon clinical observations of patients with diseases of the central nervous system and on monkeys with surgically-induced lesions of structures affected by diseases in his patients. Denny-Brown viewed dystonia as resulting from an imbalance of reflex responses to natural stimulation, both tonically and phasically. The evidence for this view came from demonstration of alterations of dystonic postures by natural vestibular, cutaneous, proprioceptive and visual stimuli. His formulations remain highly useful to clinicians faced with a bewildering variety of postural and movement disorders.