Overwintering ofChymomyza amoena larvae in apples in Michigan and preliminary studies on the mechanism of cold hardiness

Summary Chymomyza amoena, a member of the family Drosophilidae, is now breeding in fallen apples in the state of Michigan.C. amoena larvae can overwinter in fallen apples, completing development and emerging as adults in the summer. Cold resistance during the overwintering phase may not depend upon the accumulation of glycerol or other sugar alcohols.     

Maternal influences on cardiovascular pathophysiology

Elevated blood pressure (BP) is of special clinical significance because of its association with pathophysiologies such as heart disease, renal failure, and stroke. We described the development of a protocol for use with hypertensive rats in which prepubertal exposure to a high salt (8% NaCl) diet results in a pathophysiological syndrome including rapid increase in BP, failure to maintain normal weight gain, renal damage, cerebrovascular lesions, and early mortality. These phenomena are described for the inbred spontaneously hypertensive rat (SHR), and for reciprocal F₁ hybrids of a cross between SHR and the Dahl salt-sensitive (SS/Jr) inbred strain. The study with reciprocal F₁s revealed striking effects of maternal environment on pathophysiological response to a high salt diet. F₁s nurtured by SHR mothers weighed less at 35 days of age, and after exposure to the high salt diet suffered more rapid BP increases, greater incidence of stroke, body weight loss, and mortality, than F₁s nurtured by SS/Jr dams. These results suggest that maternal mediation of the nutritional status of the animal may play an important role in determining susceptibility to elevated BP and subsequent pathophysiology associated with exposure to a high salt diet. The implication of these findings for human hypertension is briefly discussed.     

Difference of the inhibitory action of verapamil on the positive inotropic effect of Ca2+ between spontaneously hypertensive and normotensive rat myocardium

Verapamil, a calcium entry blocker, had a greater inhibitory effect on the positive inotropic effect of excess Ca2+ in SHR than in NWR, suggesting that the cardiac responsiveness to verapamil was enhanced in SHR.     

Donor origin of the in vitro hematopoietic microenvironment after marrow transplantation in mice

Summary Bone marrow stroma from radiochimeric mice was established in culture. The polymorphic enzyme glucose phosphate isomerase (GPI) was used to determine the proportions of donor and recipient present in the original bone marrow and in cultured stroma. Bone marrow initially containing 95% donor GPI, when cultured and subsequently passaged for up to 8 weeks remained about 70% donor GPI. We conclude that many cultured stromal cells are donor derived in our radiochimeras and these are probably of hematopoietic origin.     

Local adjuvants: the influence of sodium dodecylbenzene sulphonate on immunization with aerosolized antigen.

Guinea-pig respiratory and serum antibody responses were enhanced following exposure to aerosols of bovine IgG2 dissolved in solutions of sodium dodecylbenzene sulphate (SDBS). Enhanced response was seen in both primary and secondary immunization. Cell-mediated immune response (indirect macrophage migration influencing test) was not altered by SDBS. Results are discussed with a view to the possible utility of SDBS as adjuvant for prophylactic immunization.