Premature chromosome condensation induced by electrofusion.

Premature chromosome condensation of G1, G2, and S-phase chromosomes has been achieved by the use of electrofusion in the fusion of Chinese hamster ovary (CHO) cells and HeLa cells and CHO cells with human leukocytes. Very high yields of heterokaryons, of over 80%, as well as elimination of adverse effects of chemical and viral fusion agents, facilitated induction of premature chromosome condensation of high quality.

Carotid baroreceptor unloading decreases plasma atrial natriuretic factor in hypertensive patients.

Atrial natriuretic factor (ANF) release is known to be regulated by distension of the atrial wall; other factors affecting ANF secretion have not yet been defined. In order to evaluate the effects of the reflex activation of the sympathetic nervous system on ANF plasma levels, in 11 patients with essential hypertension progressive deactivation of carotid baroreceptors was induced by 4-min graded increases in external neck tissue pressure. Carotid sinus hypotension induced progressive increases in blood pressure (BP), heart rate (HR) and forearm vascular resistance (FVR), while plasma renin activity and catecholamine concentrations did not change significantly.

Renal vasoconstrictive effect of kinins mediated by B1-kinin receptors.

The nature of the renal vascular actions of kinins, their dependence on prostaglandins and B1-kinin receptor responses were studied in functioning isolated perfused rat kidneys (IK). Lysylbradykinin (LBK), 0.28 and 0.

Atrial natriuretic factor in normal subjects and heart failure patients. Plasma levels and renal, hormonal, and hemodynamic responses to peptide infusion.

We investigated atrial natriuretic factor (ANF) in humans, measuring plasma immunoreactive (ir) ANF (in femtomoles per milliliter), and renal, hormonal, and hemodynamic responses to ANF infusion, in normal subjects (NL) and congestive heart failure patients (CHF). Plasma irANF was 11 +/- 0.9 fmol/ml in NL and 71 +/- 9.

Role of increased glomerular filtration rate in atrial natriuretic factor-induced natriuresis in the rat.

One of the major renal hemodynamic actions of atrial natriuretic factor (ANF) is to increase glomerular filtration rate (GFR). To assess the role of this effect on ANF-induced natriuresis (UNaV), diuresis (V) and kaliuresis (UKV) we performed late clamp experiments in six rats. After control periods (C), synthetic ANF (auriculin A) was infused i.

Renal hemodynamic and natriuretic effects of atrial natriuretic factor.

In this article we review the renal hemodynamic and excretory actions of atrial natriuretic factor (ANF) and consider some of the mechanisms of its vascular and natriuretic effects. ANF leads to a marked, sustained, and parallel increase in whole-organ and superficial single-nephron glomerular filtration rate (GFR) while mean blood pressure is decreased and renal blood flow (RBF) is unchanged or even decreased. The increase in GFR is caused by an efferent arteriolar vasoconstriction or by a combination of afferent vasodilation and efferent vasoconstriction.

Increases in circulating atrial natriuretic factor during immersion-induced central hypervolaemia in normal humans.

The role of atrial natriuretic factor (ANF) in modulating volume and circulatory homeostasis remains uncertain, and there has been as yet no systematic analysis of the factors promoting ANF release in humans. Since immersion in water to the neck provides a 'volume stimulus' identical to that induced by 2 litres of saline, without plasma compositional change, immersion to the neck was used to assess the ANF response to acute central blood-volume expansion. Using a radio-immunoassay that reliably detected ANF in human plasma extracts, more than 80% of plasma immunoreactive (ir) ANF was shown to elute as a single peak on reverse-phase high performance liquid chromatography, with a retention time identical to that of the synthetic 28-residue alpha-human (alpha-h) ANF.

Effects of atrial natriuretic factor on blood pressure and the renin-angiotensin-aldosterone system.

Atrial natriuretic factor (ANF) antagonizes vasoconstriction induced by numerous smooth muscle agonists and also lowers blood pressure in intact animals. ANF has particularly marked relaxant effects on angiotensin II-contracted vessels in vitro. Sensitivity to the blood pressure-lowering effect of ANF in vivo appears to be enhanced in renin-dependent models of renovascular hypertension compared with other experimental hypertensive models.

Differing hemodynamic responses to atrial natriuretic factor in two models of hypertension.

Hemodynamic responses to synthetic atrial natriuretic factor (ANF), were studied in renin-dependent two-kidney, one-clip (2K,1C) and deoxycorticosterone (DOC) salt-treated hypertensive rats as well as normotensive controls. ANF infusion (800 pmol/kg prime, 120 pmol X kg-1 X min-1 for 60 min) decreased blood pressure (BP) more in conscious 2K,1C (-24 +/- 4%) than in DOC salt-treated (-12 +/- 4%, P less than 0.05) or control rats.

Expression and secretion of biologically active human atrial natriuretic peptide in Saccharomyces cerevisiae.

A hybrid gene was constructed containing a fusion between the DNA sequences encoding the secretory precursor of the yeast mating pheromone alpha-factor and a synthetic sequence encoding a biologically active 24-amino acid carboxyl-terminal portion of the human atrial natriuretic peptide (hANP) precursor. Transformation of Saccharomyces cerevisiae with the hybrid gene resulted in the yeast cells secreting biologically active hANP into the extracellular medium. The secreted hANP was purified and found to be accurately processed at the junction in the chimeric alpha-factor/hANP protein, producing the desired mature hANP amino terminus.

Cardiovascular effects of atrial natriuretic factor in anesthetized and conscious dogs.

Atrial natriuretic factor lowers blood pressure in normotensive and hypertensive animal models. The present study examined the mechanism of the blood pressure-lowering effect in 10 normotensive dogs. Four awake dogs previously instrumented with electromagnetic flow probes for measurement of cardiac output and catheters for systemic hemodynamic and cardiac dynamic measurements were studied.

Patterns of BrdU incorporation in homogeneously staining regions and double minutes.

The replication chronology of two structural chromosome abnormalities linked to the amplification phenomenon of DNA sequences was investigated. Three cell lines containing homogeneously staining region (HSR) chromosomes (IMR-32, MK42, and COLO-320) and one line with double minutes (DM) (SW-613) were examined. Using a bromodeoxyuridine-Hoechst 33258-Giemsa method, the HSR in the three cell lines were shown to be composed of subunits that replicated their DNA throughout all portions of the S-phase of the cell cycle.

Sero-epidemiology of Toxoplasma gondii infection in young children in Nairobi, Kenya.

The exposure of 127 pre-school and young schoolchildren to Toxoplasma gondii was investigated by a serological survey of its antibody by means of the passive haemagglutination technique. The significant rise of prevalence of the antibody from 35% in pre-school to 60% in the early school age group suggests that poor sanitary habits and conditions and water shortage in primary schools may cause parasitic infection through contact between children which has not been previously suspected but should be investigated. The strange difference of prevalence of the antibody in the two sexes in the pre-school age children cannot be explained by any social aspects of life.

[Structure and biological action of the atrial natriuretic factor (auriculin)].

The studies described in this report emphasize the potential importance of atrial natriuretic factor in affecting systemic and renal hemodynamics, sodium excretion and components of the renin-angiotensin-aldosterone system. It should be emphasized, however, that at present there is no direct and unequivocal evidence that ANF is secreted into the blood. Until this is done and until the factors that regulate its secretion have been established, its potential physiological role must remain speculative.

Atrial natriuretic factor (auriculin): structure and biological effects.

Atrial natriuretic factor (ANF) is a recently discovered peptide present in secretory granules specifically found in atrial muscle cells. Multiple structurally related peptides have been isolated from atrial tissues, all of which are derived from a common 152-amino-acid precursor. ANF induces profound natriuresis and diuresis in experimental animals and also causes relaxation of precontracted vascular smooth muscle.

Effect of atrial natriuretic factor on blood pressure, renin, and aldosterone in Goldblatt hypertension.

We previously provided evidence that atrial natriuretic factor (ANF) antagonizes angiotensin II-induced vascular contractility and angiotensin II-stimulated aldosterone production by isolated adrenal cells. To examine the importance of these effects in vivo, synthetic ANF (auriculin A) was administered intravenously (2 micrograms/kg bolus followed by 0.3 microgram/kg/min constant infusion) to conscious, unrestrained two-kidney, one-clip and one-kidney, one-clip rats on normal sodium intake and their sham-operated controls.

[Detection by the immunoenzymatic test ELISA of IgM anti-Cysticercus cellulosae antibodies in the cerebrospinal fluid in neurocysticercosis].

IgM antibodies against Cysticercus cellulosae in the cerebrospinal fluid (CSF) was demonstrated by ELISA immunoenzymatic assay in neurocysticercosis. CSF samples of 41 patients were analyzed for this purpose. Diagnosis was neurocysticercosis in 26 and neurosyphilis in 5; abnormalities were not registered in the other 10 cases.

Effects of auriculin (atrial natriuretic factor) on blood pressure, renal function, and the renin-aldosterone system in dogs.

Auriculin is a potent vasoactive and natriuretic peptide that was recently isolated and purified from rat atrial tissue. Since this peptide could be of great importance for renal, cardiovascular, and volume homeostasis, its functional properties have been characterized in dogs. The effects of synthetic auriculin on renal function, mean blood pressure, plasma renin activity, renin secretory rate, and plasma aldosterone levels were determined.

Immunoenzymatic assay of anti-diphtheric toxin antibodies in human serum.

An enzyme-linked immunosorbent assay was developed for measuring immunoglobulin G anti-diphtheric toxin antibodies in human serum. The assay was done in plastic plates coated with purified diphtheric toxoid. Since a straight-line relationship was found between logs of extinction values and of antibody concentrations, with a very constant slope, serum titers could be expressed as log10 of the serum dilution corresponding to a definite optical density, such as 0.