Efficacy of antihypertensive drugs.

The magnitude of the fall in blood-pressure in response to an antihypertensive drug depends on the level of the pretreatment pressure, and there is a direct relationship between the two in that the higher the pretreatment pressure the greater the fall in pressure in response to treatment. This simple relationship is inherent in the practical situation of titrating the diastolic blood-pressures of a group of hypertensive patients to a predetermined level. It is assumed that notionally the dose of an antihypertensive drug can be increased in all patients until the diastolic pressure is reduced to the predetermined level.

Maternal uterine vascular lesions in the hypertensive complications of pregnancy.

To establich hemochorial placentation, the nonvillous trophoblast breaches the spiral arteries in the basal decidua and later migrates down the arteries as far as the parent radial arteries in the myometrium. Interactions between the endovascular trophoblast and the tissues of the maternal vessel wall (physiological changes) adapt these arteries to the uteroplacental arteries, and these large caliber vessels empty into the intervillous space. Loss of reactive musculoelastic vascular tissue results in a lowering of peripheral resistance, permitting a greatly increased blood flow into the intervillous space.

Histone methylation. Its occurrence in different cell types and relation to histone H4 metabolism in developing trout testis.

Histone methylation in developing trout testis has been observed in the diploid stem cells and primary spermatocytes, which actively synthesize DNA and histones. In spermatids, histone methylation is minimal and so probably plays no role in the replacement of histones by protamine which is characteristic of this cell type. No turnover of histone methyl groups could be detected over several hours, so that unlike acetylation or phosphorylation of histones, methylation in this tissue appears to be a stable, irreversible modification.

Sites of in vivo histone methylation in developing trout testis.

Specific lysyl residues of trout testis histones H3 and H4 are methylated partially during rainbow trout spermatogenesis. Histones H1, H2A, H2B, and protamine are not methylated. The single site (lysine 20) in histone H4 and the two major sites (lysines 9 and 27) in histone H3 are homologous to those determined for other organisms, but an additional minor site (lysine 4) occurs in histone H3.

Traumatic vertebral artery pseudoaneurysm following chiropractic manipulation.

A vertebral artery pseudoaneurysm accompanied by serious neurological injury was seen in a 42-year-old woman who had undergone chiropractic manipulation of the neck. Such manipulation is a potential cause of neurological injury due to trauma to the cervical spine and the major vessels of the neck. The arterial pattern in this case was similar to that of angiodysplasia except for narrowing and irregularity of the vertebral artery.

Cerebral angiographic changes associated with tuberous sclerosis.

Two patients with tuberous sclerosis were examined angiographically. In one, direct left carotid angiography showed a contralateral shift of the anterior cerebral artery and lateral displacement of the middle cerebral artery. On the lateral series, increase in the sweep of the anterior cerebral artery as well as stretching of the opercular branches of the middle cerebral artery were noted in the early arterial phase.

Arterial blood gases in conscious rats exposed to hypoxia, hypercapnia, or both.

Adult male rats were anesthetized and catheters were implanted in the caudal artery. Soon after recovery from short-lasting anesthesia, a total of 20 groups of six each were individually exposed to five different oxygen levels varying from 21.0 to 9.

The hormonal control of activity of skeletal muscle phosphorylase kinase. Amino-acid sequences at the two sites of action of adenosine-3':5'-monophosphate-dependent protein kinase.

Two tryptic phosphopeptides containing the sites on the alpha and beta subunits of phosphorylase kinase which are phosphorylated by protein kinase, dependent on adenosine 3':5'-monophosphate (cyclic AMP), have been isolated and their amino acid sequences have been determined. 32P-labelled phosphorylase kinase, containing 1.9 mol phosphate per mol enzyme, was digested with an equimolar quantity of trypsin for 2.