SUMMARY A method is described for diagnosing the presence or absence of a conceptus soon after mating or insemination. It is applicable to a wide range of mammals and tests in the cow, sheep and pig have given an accuracy of approximately 90%. The method is based on the detection of a functional or regressed corpus luteum at a fixed time after mating by measuring the concentration of progesterone in peripheral blood. It is relatively simple to carry out.

No abstract

Background. Hyponatremia in patients with small cell lung cancer (SCLC) is a common clinical problem usually attributed to tumor secretion of arginine vasopressin (AVP). It recently was shown that some SCLC cell lines produce atrial natriuretic peptide (ANP). The purpose of this investigation was to determine the frequency and clinical consequences of secretion of ANP by SCLC and the relative contribution of ANP and AVP to the hyponatremia associated with this disease. Methods. Levels of ANP and AVP were measured in 23 SCLC cell lines and 23 other human tumor cell lines. Also, ANP and AVP levels were determined in plasma samples from 69 patients with active small cell carcinomas. Results. Of the 23 SCLC lines, 16 (70%) had elevated ANP levels. Only two (8.7%) had elevated AVP levels, and these two also had elevated ANP levels. One of the ANP‐producing cell lines was derived from a hyponatremic patient with no other apparent explanation for a low sodium level. However, the four cell lines with the highest levels of ANP were derived from patients who were not hyponatremic. Two other human tumor lines also produced ANP. Of the 69 patients with SCLC, 21 (30.4%) had elevated ANP levels, whereas 4 (6%) had elevated AVP levels. Fifteen of these patients were hyponatremic during their clinical course (21.7%). Of the eight patients who were hyponatremic when samples were collected, two had e vated ANP levels, and only one had elevated AVP levels Six patients (8.7%) had symptoms of postural hypotension, possibly attributable in some cases to tumor secretion of ANP. Conclusions. The majority of SCLC lines produce ANP, and a minority produce AVP. Secretion of ANP may result in hyponatremia and/or postural hypotension. However, secretion of either or both of these peptic does not account for all cases of hyponatremia in patient with SCLC and does not necessarily cause clinical manifestations.

No abstract

in plasma progesterone levels in the ewe during the estrous cycle, and during pregnancy in intact and ovariectomized sheep. Can, J. Anim. The progesterone concentration in the peripheral plasma was measured sequen-