Carboxyhemoglobinemia, polycythemia, cardiomegaly, and cardiovascular function in the anesthetized rat.

The effects of carbon monoxide (CO), polycythemia (PC), and cardiomegaly (CM) on cardiovascular function were investigated in adult rats in which the latter two conditions were induced by 500 ppm CO inhalation for 5-6 weeks. Using an anesthetized open-chest preparation, these rats were compared with normal rats. With CO + PC + CM present, resting cardiac index, stroke index, stroke work, and minute work were elevated (heart rate also in the conscious state), while left ventricle end-diastolic pressure (LVDP) was normal.

Cardiomegaly due to myocyte hyperplasia in perinatal rats exposed to 200 ppm carbon monoxide.

Exposure to carbon monoxide (CO) during the fetal and neonatal period was used to evaluate cardiac ventricular regional weight and myocyte growth response to an increased hemodynamic load. Date-mated Sprague-Dawley rats inhaled 200 ppm CO from day 7 of pregnancy until parturition; another group of pregnant rats inhaled room air. At birth, pups from these two groups were subdivided into four groups: (1) control group (AIR/AIR), that was maintained in room air in utero and post-partum; (2) AIR/CO group, which received CO only after birth; (3) CO/CO group, which received CO exposure in utero and post-partum; and (4) CO/AIR group, which received CO exposure in utero but was maintained in room air post-partum.

Cardiomegaly and haemodynamics in rats with a transplantable growth hormone-secreting tumour.

To investigate cardiovascular changes in experimental acromegaly, a growth hormone-secreting tumour (MtT-W-15) was implanted in adult female rats. Somatic and tumour growth occurred steadily during the 8 week study period, as did an increase in serum growth hormone titre. Weight of left ventricle and right ventricle increased directly with tumour growth, both on an absolute basis and when compared with normal rats of equal body weight.

Radiometric assays of N-acetylglucosaminylphosphotransferase and alpha-N-acetylglucosaminyl phosphodiesterase with substrates labeled in the glucosamine moiety.

The assay of fibroblast and leukocyte-N-acetylglucosaminylphosphotransferase with alpha-methylmannoside acceptor and commercially available UDP-[3H or 14C]N-acetylglucosamine donor was modified to yield low background and consequently high sensitivity and reliability comparable to those obtained with the synthetically made [beta-32P]UDP-N-acetylglucosamine donor. This was achieved by an additional elution step that removed free [3H or 14C]N-acetylglucosamine which appeared to be the breakdown product responsible for the high background. In addition, the [3H or 14C]N-acetylglucosamine-1-phospho-6-alpha-methylmannoside product of the transfer reaction was then isolated and, following desalting, could serve as a substrate for the assay of alpha-N-acetylglucosaminyl phosphodiesterase.

Persistent cardiomegaly induced by carbon monoxide and associated tachycardia.

To explore the effect of persistent cardiomegaly on cardiovascular function, groups of newborn rats inhaled up to 500 ppm CO for 33 days, after which development continued in ambient air. In the first two experiments hemodynamics were assessed by use of an anesthetized open-chest preparation; in the third experiment heart rate (HR) and arterial systolic blood pressure (BP) were monitored by auscultation in the conscious state. In all three experiments weights of left ventricle (LV) plus interventricular septum (S), both ventricles (2V), and right ventricle (RV) were significantly greater by prediction on the basis of body weight (BW) than for normal rats at 87-97, 166-176, and 337-339 days of age in females and 98-108, 177-183, and 337-339 days of age in males.