Blood Ferrokinetics in Normal Man

• Text
• PDF

Abstract

The clearance of radioiron from plasma and its appearance in circulating erythrocytes in normal subjects are studied. The importance of correcting for plasma iron fluctuations and for mean body hematocrit is illustrated. The data are analyzed by probability theory to determine relationships between intravascular and extravascular iron. Two refluxes are described, one of about 7 particles of every 100 leaving the plasma, and the second of about 23. The return times of these are about 5 hours and 8 days, respectively.

Authors

Fazle Hosain, George Marsaglia, Clement A. Finch

Measurement of Gastrointestinal Protein Loss Using Ceruloplasmin Labeled with ⁶⁷Copper

• Text
• PDF

Abstract

Ceruloplasmin labeled with 67copper and administered intravenously to dogs, control human subjects, and patients with excessive gastrointestinal loss was shown to fulfill the requirements for a label for quantification of gastrointestinal protein loss. The radiocopper moiety was poorly absorbed from the gastrointestinal tract, not actively secreted into the intestinal tract, and did not alter significantly the metabolism of ceruloplasmin. Approximately 70% of the body pool of ceruloplasmin in both dog and man was within the intravascular space. In control human subjects the mean ceruloplasmin concentration was 30 mg per 100 ml with total circulating and total body ceruloplasmin pools of 15.5 and 22 mg per kg, respectively. In patients with excessive gastrointestinal protein loss secondary to intestinal lymphangiectasia, the serum ceruloplasmin concentration was reduced to 16 mg per 100 ml with a comparable reduction in the total circulating and total body ceruloplasmin pools to 8.8 and 12 mg per kg.

Authors

Thomas A. Waldmann, Anatol G. Morell, R. Dean Wochner, Warren Strober, Irmin Sternlier

Studies on the Epidemiology of Escherichia coli Infections. V. Factors Influencing Acquisition of Specific Serologic Groups

• Text
• PDF

Abstract

Stool carrier rates of Escherichia coli serogroups 4, 6, and 75 were determined on admission and discharge for 190 patients. Persons who were in the hospital 3 weeks or longer had an intestinal carrier rate of 46% compared to a rate of 28% in individuals who had no recent hospital contact. Treatment with broad spectrum antibiotics increased the susceptibility for acquisition of certain specific serologic groups. This was apparently not related to replacement of sensitive E. coli by drug-resistant forms. Studies were made to determine the environmental source for colonization of hospitalized patients and the risk of urinary infection in stool carriers of these strains. A survey of inanimate objects of medical and urological wards demonstrated infrequent isolation of 04, 06, and 075, indicating that extraintestinal foci were an unlikely source for hospital-acquired E. coli. Hemagglutination titers with determination of group-specific O antibody failed to demonstrate any deficiency in hospitalized patients who became colonized with certain coliforms. Similarly, no significant deficit in group-specific serum antibody was found in patients who were community carriers of E. coli 04, 06, or 075. Despite a high rate of acquisition of E. coli serogroups 4, 6, and 75 in the stools of hospitalized patients, only those patients undergoing urinary tract manipulation developed bacteriuria.

Authors

Richard H. Winterbauer, Marvin Turck, Robert G. Petersdorf

Intestinal Transport of Cystine and Cysteine in Man: Evidence for Separate Mechanisms

• Text
• PDF

Abstract

Cystine and cysteine are transported by energy-dependent, mediated processes in human gut. When either of these amino acids is transported, only cysteine is recovered intracellularly, indicating that cystine is reduced to cysteine after achieving an intracellular location. In contrast to results with cystine, cysteine uptake is not defective in gut from cystinuric patients, nor do lysine and arginine compete with cysteine for transport. It is, therefore, concluded that cystine and cysteine are transported by different mechanisms, and that only the cystine transport mechanism is defective in cystinuria.

Authors

Leon E. Rosenberg, John C. Crawhall, Stanton Segal

Studies on the Absorptive Defect for Triglyceride in Abetalipoproteinemia

• Text
• PDF

Abstract

The nature of the gastrointestinal absorptive defect for triglyceride in three subjects with abetalipoproteinemia has been investigated by studying peroral biopsies of the gastrointestinal mucosa. The following conclusions were reached.

Authors

P. O. Ways, C. M. Parmentier, H. J. Kayden, J. W. Jones, D. R. Saunders, C. E. Rubin

The Mechanism of Suppression of Proximal Tubular Reabsorption by Saline Infusions

• Text
• PDF

Abstract

The mechanism by which expansion of extracellular fluid volume with isotonic saline suppresses reabsorption in the proximal tubule was studied in rats by examining the relations among glomerular filtration rate (GFR), absolute and fractional reabsorption of filtrate, intrinsic reabsorptive capacity (rate of reabsorption per unit tubular volume), transit time, and tubular volume.

Authors

Floyd C. Rector Jr., Jack C. Sellman, Manuel Martinez-Maldonado, Donald W. Seldin

Thyrocalcitonin and the Response to Parathyroid Hormone

• Text
• PDF

Abstract

1) In the absence of the thyroid gland, the infusion of parathyroid hormone leads to a prompt rise in plasma calcium and to prompt increase in the rate of excretion of calcium in the urine.

Authors

Constantine Anast, Claude D. Arnaud, Howard Rasmussen, Alan Tenenhouse

The Concentration Dependence of Active Potassium Transport in the Human Red Blood Cell

• Text
• PDF

Abstract

The relation between the active potassium influx in the human red blood cell and the extracellular potassium concentration does not appear to be consistent with the Michaelis-Menten model, but is adequately described by a model in which two potassium ions are required simultaneously at some site or sites in the transport mechanism before transport occurs. The same type of relation appears to exist between that portion of the sodium outflux that requires the presence of extracellular potassium and the extracellular potassium concentration. Rubidium, cesium, and lithium, which are apparently transported by the same system that transports potassium, stimulate the potassium influx when both potassium and the second ion are present at low concentrations, as is predicted by the two-site model.

Authors

John R. Sachs, Louis G. Welt

Modification by Beta-Adrenergic Blockade of the Circulatory Responses to Acute Hypoxia in Man

• Text
• PDF

Abstract

In 17 healthy men, beta-adrenergic blockade reduced significantly the tachycardia and the elevation of cardiac output associated with inhalation of 7.5% oxygen for 7 to 10 minutes.

Authors

David W. Richardson, Hermes A. Kontos, A. Jarrell Raper, John L. Patterson Jr.

A Receptor Mechanism for the Inhibition Of Insulin Release by Epinephrine in Man

• Text
• PDF

Abstract

Normal adult men and women have been infused with epinephrine, 6 μg per minute, during lipolytic blockade with nicotinic acid, beta-adrenergic blockade with propranolol and Butoxamine, and alpha-adrenergic blockade with phentolamine. Epinephrine infusion was associated with low serum levels of immunoreactive insulin (IRI) except when phentolamine was given simultaneously. These findings are compatible with an alpha receptor mechanism for the epinephrine inhibition of insulin release. Phentolamine had no blocking effects on the tachycardia and widened pulse pressure or lipolytic stimulation by epinephrine, whereas both propranolol and Butoxamine blocked lipolysis, tachycardia, and widened pulse pressure. These findings are consistent with an alpha receptor blocking action for phentolamine and beta receptor blocking action for propranolol and Butoxamine. Inhibition of lipolysis by nicotinic acid did not alter IRI or glucose responses to epinephrine. It is concluded that the lipolytic effect of epinephrine is unrelated to its effects on IRI release. Lipolytic blockade by nicotinic acid also did not change IRI or glucose in fasting subjects or their responses to a glucose infusion, 300 mg per minute. These observations appear to conflict with the Randle hypothesis (the glucose-fatty acid cycle) and raise some doubt as to whether plasma FFA concentrations are direct determinants of glucose or IRI concentrations in normal man.

Authors

Daniel Porte Jr.

A Microperfusion Study of Bicarbonate Accumulation in the Proximal Tubule of the Rat Kidney

• Text
• PDF

Abstract

In order to determine whether HCO3- gains access to the proximal tubular lumen from a source other than the glomerular filtrate, we carried out microperfusion experiments on isolated segments of rat proximal tubules in vivo. The perfusion fluid was essentially free of HCO3- and of a composition that prevented net absorption of sodium and water.

Authors

Norman Bank, Hagop S. Aynedjian

Human Placental Lactogen: Studies of Its Acute Metabolic Effects and Disposition in Normal Man

• Text
• PDF

Abstract

The acute metabolic effects and disposition of human placental lactogen (HPL) have been studied in 15 men and 8 women during continuous intravenous infusions. The mean plasma half-life, metabolic pool size, and turnover rate of HPL are comparable to the values previously reported for human growth hormone (HGH). From the data presented, we calculate that the placenta secretes approximately 290 mg HPL daily at term.

Authors

Paul Beck, William H. Daughaday

Increased Plasma Arginine Vasopressin in Clinical Adrenocortical Insufficiency and Its Inhibition By Glucosteroids

• Text
• PDF

Abstract

Trichloroacetic acid extracts of plasma were fractionated on a CG-50 resin column and the 50% acetic acid eluents chromatographed on silicic acid-impregnated glass paper in butanol-acetic acid-water. The specific arginine vasopressin (AVP) zone was eluted and assayed for antidiuretic activity in the diuretic rat. Thioglycolate inactivation was used to confirm AVP activity. Recovery of as little as 4 μU AVP per ml plasma ranged between 80 and 90%. In normal subjects after an overnight fast, plasma AVP ranged between 2.5 and 10.0 μU per ml. AVP secretion was inhibited by hemodilution and stimulated with nicotine and hypertonic saline. Plasma AVP was absent in patients with diabetes insipidus even after neurohypophyseal stimulation. Plasma AVP was abnormally elevated during mild dehydration and remained above the normal range despite hemodilution in patients with untreated adrenocortical insufficiency demonstrating a delayed water diuresis. Glucosteroid therapy lowered plasma AVP to normal in dehydrated patients. A normal diuretic response to hydration was accompanied by a fall in plasma AVP to zero in steroid-treated patients. These findings suggest that hypersecretion of AVP may play an important role in the abnormal water metabolism of adrenocortical insufficiency and that the glucosteroids promote normal water diuresis by inhibiting the secretion of AVP from the neurohypophysis.

Authors

Abdul B. J. Ahmed, Barbara C. George, Carlos Gonzalez-Auvert, Joseph F. Dingman

The Inhibitory Effect of Heme on Heme Formation In Vivo: Possible Mechanism for the Regulation of Hemoglobin Synthesis

• Text
• PDF

Abstract

1) The effect of hemin on heme synthesis was studied in vivo. Heme synthesis was measured by determining red cell 59Fe uptake and glycine-2-14C incorporation into red cell hemin in normal CF1 female mice.

Authors

Robert C. Gallo

Lung Tissue Resistance in Diffuse Interstitial Pulmonary Fibrosis

• Text
• PDF

Abstract

1) Measured during spontaneous breathing in ten patients with diffuse interstitial lung disease, total pulmonary resistance averaged 3.53 ± 1.56 cm H2O per L per second; airway resistance, 1.63 ± 0.79 cm H2O per L per second; and lung tissue resistance, 1.90 ± 0.95 cm H2O per L per second (range, 0.89 to 3.96). The lung tissue resistance was on an average about four times higher in patients with lung fibrosis than in ten healthy persons of the same age. No significant difference in airway resistance was found between healthy subjects and patients.

Authors

H. Bachofen, M. Scherrer