Ultrasonographic appearance of the bovine conceptus from days 10 through 20

The bovine conceptus was monitored in 19 heifers by intrarectal ultrasonic imaging from the day an embryonic vesicle was first detected (mean, day 11.7 +/- 0.4; range, days 10 to 17) until detection of the embryo proper (mean, day 20.3 +/- 0.3). Fifteen heifers maintained the conceptus and 4 heifers apparently lost the conceptus. In the heifers that maintained the conceptus, 73% of the embryonic vesicles were classified as spherical (mean diameter, 2.8 +/- 0.2 mm) and 27% were classified as oblong (mean dimensions, 2.0 +/- 0.0 mm and 4.5 +/- 1.0 mm) on the day of first detection. All vesicles were in the uterine horn ipsilateral to the corpus luteum. The vesicles increased in length from the day of first detection. On the average, the vesicle occupied all of the ipsilateral uterine horn on day 16.9 +/- 0.6 and all of the contralateral horn on day 19.6 +/- 0.9. During elongation, the vesicle remained at an approximate height of 2 mm throughout its length, but developed a localized enlargement or bulge on mean day 19.7 +/- 0.2. The embryo proper was detected within the bulge in all 15 heifers. A heartbeat (mean, 188 +/- 4.8 beats/min) was detected on the first day of detection of the embryo proper (8 heifers) or on the following day (7 heifers). The mean length of the interovulatory interval in the 4 heifers that apparently lost the embryonic vesicle was not significantly different from that of nonbred heifers. The vesicles were lost (not ultrasonographically detectable) on days 17 (2 heifers) and 19 (2 heifers).(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation and partial characterization of the amino-terminal propeptide of type II procollagen from chick embryos

The amino-terminal propeptide from type II procollagen was isolated from organ cultures of sternal cartilages from 17-day-old chick embryos. The procedure provided the first isolation of the propeptide in amounts adequate for chemical characterization. The propeptide had an apparent molecular weight of 18000 as estimated by gel electrophoresis in sodium dodecyl sulfate. It contained a collagen-like domain as demonstrated by its amino acid composition, circular dichroism spectrum, and susceptibility to bacterial collagenase. One residue of hydroxylysine was present, the first time this amino acid has been detected in a propeptide. The peptide contained no methionine and only two residues of half-cystine. Antibodies were prepared to the propeptide and were used to establish its identity. The antibodies precipitated type II procollagen but did not precipitate type II procollagen from which the amino and carboxy propeptides were removed with pepsin. Also, they did not precipitate the carboxy propeptide of type II procollagen. The data demonstrated th at the type II amino propeptide was similar to the amino propeptides of type I and type III procollagens in that it contained a collagen-like domain. It differed, however, in that it lacked a globular domain as large as the globular domain of 77-86 residues found at the amino-terminal ends of the pro alpha 1 chains of type I and type III procollagens.

Habituation of infants' cardiac response to speech stimuli

In an attempt to explore the relation between the amount of variability in a stimulus and rate of habituation to that stimulus, 4 groups of infants 4 1/2--5 1/2 months of age were presented with repeated speech stimuli which were synthesized exemplars of [baba], natural exemplars of [baba] or [kaba], or novel syllables of each trial. Infants' cardiac responses to the auditory stimuli were recorded, and the number of trials to a proportional criterion of habituation of the heart-rate decelerative response was determined. Infants were found to habituate most rapidly to the synthesized [baba] stimulus which remained constant across trials and least rapidly to the speech syllables which changed from trial to trial.