Activation of adenylate cyclase in cultured fibroblasts by trypsin

Adenylate cyclase activity measured in membranes of cultured normal rat kidney (NRK) fibroblasts was markedly increased by prior treatment of the intact cells with trypsin. Cell population density influenced the extent of activation observed. Trypsin treatment of sparse cells significantly enhanced adenylate cyclase activity, whereas similar treatment of confluent cells caused only a slight increase in adenylate cyclase activity. The degree of activation noted after trypsin treatment also varied depending on the adenylate cyclase function measured. Activity determined in the presence of GTP alone showed the greatest increase after trypsin treatment. Similar enhancement of adenylate cyclase activity of a washed cell membrane preparation was achieved by the addition of low concentrations of trypsin directly to the adenylate cyclase reaction mixture. The membranes of confluent NRK fibroblasts initially exhibited higher adenylate cyclase activity than did membranes of sparse cells. The present results suggest that this change in adenylate cyclase activity at cell confluence is not due to an increase in the amount of adenylate cyclase in the cell membrane but rather to a change in membrane components that regulate its activity. Proteolytic activation of adenylate cyclase appears to result from degradation of cell membrane proteins that modulate the activity of this enzyme.

A test for rare male mating advantage at an "enzyme locus" in Drosophila

Matings between Drosophila pseudoobscura strains differing at the amylase (Amy) locus were observed in Elens-Wattiaux chambers. Males homozygous for either Amy1.00 or Amy0.84 alleles in the CH gene arrangement enjoyed a mating advantage when moderately rare, but none when quite rare. The minority male advantage for strains differing at the Amy locus, and other loci linked to it, was comparable in size to that observed between strains carrying the ST or CH gene arrangements, and either alike or different at the Amy locus. Although some features of our results are puzzling, there is evidence that the Amy locus and others for which it serves as a marker have effects on mating behavior which include some degree of rare male mating advantage.

Localization of serum-derived alpha 2 macroglobulin in cultured cells and decrease after Moloney sarcoma virus transformation

NRK cells and many other cultured fibroblasts were found to contain the protease inhibitor, alpha 2 macroglobulin (alpha 2M). This alpha 2M is present as a result of uptake of alpha 2M from the calf serum in the culture medium. Some of this alpha 2M is released back into the medium. In radiolabeling experiments with 14C-amino acids, no radioactivity was detected in intracellular or extracellular alpha 2M. Fluorescence microscopy of fixed cells using rhodamine-labeled antibodies indicated that alpha 2M is present in vesicular organelles different from primary lysosomes. Fluorescence microscopy of living cells shows that rhodamine-labeled alpha 2M (rhodamine-alpha 2M) is taken up into similar structures. Of the many cell lines examined, Moloney sarcoma virus-transformed cells had the lowest amounts of alpha 2M. Some of the effects of serum on the behavior of cultured cells could be a consequence of inhibition of cellular proteases by alpha 2M.

Gas exchange and acid-base regulation in the blood and extraembryonic fluids of the developing chicken embryo

Measurements of pH, PCO2, PO2 and total CO2 were recorded simultaneously in samples of chorioallantoic fluid, amnionic fluid and blood of the chorioallantoic artery from chicken embryos on days 8, 10, 12, 14, 16, 17 and 18 of incubation. During the incubation period studied, PCO2 levels similarly increased in the blood and extraembryonic fluids. The pH of the blood and amnionic fluid remained approximately constant while the chorioallantoic fluid became progressively acidic. Increases of amnionic fluid and blood HCO-3 indicated that respiartory compensation processes regulate pH. In addition, the disappearance of chorioallantoic fluid HCO-3 suggested that reabsorptive processes may conserve these ions and contribute them to the amnionic fluid by either a direct transfer through the amnioallantoic membrane or by way of the chorioallantoic vascular system.

Experimental cryptorchidism in adult male rats: histological and hormonal sequelae

Mature male rats were rendered cryptorchid and followed for up to nine weeks during which serial blood specimens were obtained for multiple hormonal analyses; serial testicular samples were obtained as well. In contrast with control animals, cryptorchid rats showed transient rises in FSH which returned to normal at the end of the study; estrogen levels were high in the final weeks. Plasma testosterone levels were unchanged and LH levels changed little. Light and electron microscopic studies of testicular biopsy specimens showed prompt disruption of spermatogenesis which became more extensive with time. Sertoli cells underwent multiple changes including increased lipid storage and phagocytosis of spermatozoa. Comparisons are made between the sequence of hormonal changes and that of histological changes. In addition, questions are raised concerning the ways in which Sertoli cells are affected by experimental cryptorchidism.

Effects of estradiol-17beta on cholesterol metabolism in the rat: a study using a deuterium label and mass spectrometry

The effect of estradiol-17beta (E2) on several important aspects of cholesterol metabolism were examined in the rat. Ovariectomized rats were implanted subcutaneously with 1 or 4 cm. of silastic tubing packed with E2, and were also given 2% D2O in their drinking water. The E2 diffused slowly out of the implants and the two different lengths of tubing resulted in constant E2 blood concentrations of either high (4.0 cm) or physiological (1.0 cm) levels. By measuring the rate of incorporation of deuterium into plasma cholesterol by mass spectrometry over a period of 42 days, we determined the rate constant of cholesterol synthesis and cholesterol turnover time and rate under two E2 dosage conditions. E2 treatment did not affect the rate constant of cholesterol turnover rate (mg synthesized/day) showed a dose dependent reduction with increasing doses of E2. This may be secondarily caused by E2's suppression of both food intake and subsequent weight gain; E2 treated animals are smaller and, therefore, synthesize less cholesterol per day. Additionally, E2 treated animals showed a rise in plasma cholesterol levels and in the fraction of labeled cholesterol appearing in the plasma.

The influence of casting solvent composition on structure and permeability of acrylic-methacrylic ester copolymer films

Decrease in the solvation of polymer by inclusion of ethanol in the acetone casting solution resulted in greater permeability to urea of cast acrylate-methacrylate film. The greater permeability was accompanied particularly by a decrease in pore size and increase in pore number, despite the absence of change in pore area. A decrease in cohesiveness in the film was suggested by the decrease in tortuosity of the pores as seen by scanning electron microscopy; also, water uptake was increased when the film was cast from an ethanolic solution. The results support the view that, in practice, the composition of the solvent, by its effect on microstructure, can affect the function of the film cast from it.

Crystalloid versus colloid hemodilution in man

The effects of intraoperative prebleeding and hemodilution with lactated Ringer's solution on hemodynamics, oxygen transport and lung water were studied in four patients undergoing extensive surgical procedures. The results were contrasted with those previously obtained from hemodilution of a group of patients with Plasmanate. The mean volumes bled were 1,950 milliliters in the lactated Ringer's solution group and 1,697 milliliters in the Plasmanate group. The posthemodilution hematocrit values were 26 per cent and 25 per cent, respectively. Cardiac output increased to only 115 per cent of the base line in the lactated Ringer's solution group but to 161 per cent in the Plasmanate group. Systemic oxygen transport was reduced to 80.0 per cent in the lactated Ringer's solution group, while in the Plasmanate group, it rose to 109.7 per cent. The lung water and alveolar arterial oxygen gradients were increased to 134 and 112 per cent in the lactated Ringer's solution group, whereas in the Plasmanate group, the lung water was reduced to 82 per cent, and the arterial alveolar oxygen gradient was reduced to 75 per cent. In these selected patients, hemodilution was well tolerated. Plasmanate hemodilution resulted in better compensatory changes than did hemodilution with lactated Ringer's solution in terms of oxygen transport and changes in lung water.

Combined cystometry and perineal electromyography in the diagnosis and treatment of neurogenic urinary incontinence

Function of the bladder and periurethral striated muscle was determined simultaneously by combined cystometry and electromyography studies in 120 patients. The coordinated tests were extremely helpful in identifying the different types of periurethral striated muscle activity in neurogenic bladder dysfunction, diagnosing the mechanism of incontinence and determining the appropriate therapy.

Intraoperative prebleeding in man: effect of colloid hemodilution on blood volume, lung water, hemodynamics, and oxygen transport

The effects of acute normovolemic hemodilution on lung water, blood volume, hemodynamics, and oxygen transport were studied. The subjects were six patients undergoing major operations, with prebleeding and hemodilution under fluoroxene and nitrous oxide anesthesia. The menatocrit was reduced form 43 to 25 percent in one step, with simultaneous infusion of Plamanate and lactated Ringer's solution. Blood volume was expanded by 5 percent by the hemodilution. The major compensation was a striking rise in cardiac output to 161 percent. Systemic oxygen transport (CO times arterial O2 content) increased despite the marked fall in oxygen-carrying capacity, and the arteriovenous O2 content difference decreased. Lung water the aveolararterial (A-a) oxygen differences were reduced. The procedure was well tolerated by this group of selected patients and homologous blood utilization was reduced.

The spectrum of colitis associated with lincomycin and clindamycin therapy

Ten cases of protracted diarrheal illness after the oral administration of lincomycin or clindamycin in standard dosages were observed in previously healthy subjects. An abrupt onset of diarrhea, crampy abdominal pain, fever, and leukocytosis was observed one to 12 days after discontinuation of the drug. Proctoscopic examination revealed erythematous friable mucosa covered with small raised, yellowish-white plaques that were sometimes confluent. Barium contrast studies of the colon demonstrated irregular shaggy mucosa, ulcerations, cobblestone appearance, and thumb printing. Rectal bipsy showed acute inflammation with pseudomembranes with focal or superficial ulcerations. All patients had a protracted course but recovered with supportive management. Follow-up barium enemas and proctoscopy were done on all patients and were normal. A history of diarrhea, fever, and mucosal changes seen on proctoscopy in a patient who has recently received one of these antibiotics should raise the possibility of colitis associated with clindamycin and lincomycin therapy.

Acute hemodilution: its effect of hemodynamics and oxygen transport in anesthetized man

The effects of acute normovolemic hemodilution on hemodynamics, oxygen transport, tissue perfusion and blood volume were studied. The subjects were four patients undergoing total hip replacement with prebleeding and hemodilution under fluoroxene and nitrous oxide anesthesia. The hematocrit was reduced to 29% and 21% by bleeding in two steps with simultaneous infusion of plasmanate and lactated Ringer's solution. The major compensation was a rise in CO to 123% and 136%. Systemic oxygen transport (COX arterial O(2) content) was only slightly reduced and the arteriovenous oxygen difference decreased. Tissue perfusion remained excellent. Blood volume was slightly expanded. The procedure was well tolerated by this group of selected patients, and homologous blood utilization was markedly reduced.

Phosphorylation of human platelet myosin

A preparation extracted from human blood platelets, which incorporates (32)P from gamma-labeled AT(32)P into one of the two light chains of platelet myosin and platelet myosin head is described. This phosphorylation, which appears to be due to an endogenous kinase, is specific for the myosin light chain in that no other protein extracted in 0.6 M KCl-15 mM Tris.HCl (pH 7.5) is phosphorylated. The phosphorylated light chain, which has been purified by gel filtration, releases the covalently bound phosphate after incubation in alkali and not after incubation in acid.

[Mitochondrial localization of enzymes linked to glycogen metabolism in the snail sperm cell]

The mitochondrial derivative of the sperm cell of the Gastropod Helix is endowed with a compartment loaded with glycogen (Personne et André, 1964). The aim of this work is to establish whether this mitochondrial glycogen is synthesized in the mitochondrial derivative itself or elsewhere in the cell. For this purpose, living sperm were first incubated in a medium containing glucose 1-phosphate, then fixed, sectioned, and stained specifically for polysaccharides by the phosphotungstic acid technique or the periodic acid-thiosemicarbazide-silver proteinate technique. Comparison with controls shows that a synthesis of glycogen occurred during the time of incubation. It can be inferred from this result that an amylophosphorylase system controlling the metabolism of polysaccharides is present in the mitochondrial derivative itself. Results obtained with the iodine technique indicate that the original glycogen molecules are elongated during the experiment. It seems probable that the amylophosphorylase system demonstrated here accounts for at least a part of the proteinaceous coat morphologically detectable around each individual glycogen particle.

Division and DNA Synthesis in the Kinetoplast of Crithidia Fasciculata

In Crithidia fasciculata division of the kinetoplast occurs prior to karyokinesis. Kinetoplast division involves the lateral replication of the nucleoid, and the subsequent constriction and ‘pinching off’ of the nucleoid and mitochondrial components. Two subunits are produced.

DNA synthesis in the kinetoplast and the nucleus is overlapping but asynchronous. Experiments for short labelling times indicate that the kinetoplast S period either precedes, succeeds or is simultaneous with the nuclear period of DNA synthesis. The kinetoplast divides in a manner in which some radioactivity is transmitted to each unit.

[Compartmentalization of enzymic activities in the spermatozoa of certain gastropod mollusca. I. Localization of dehydrogenases]

By electron-microscope cytochemistry, succinate- and NADH2-tetrazolium reductase activities have been demonstrated in spermatozoa of the pulmonate gastropods, Testacella and Helix. Enzyme reaction product is restricted to the mitochondrial compartment named the secondary helix; this compartment is derived from the matrix of typical mitochondria. ‘Mitochondrial metamorphosis’ during spermiogenesis accomplishes the segregation of dehydrogenases to this matrical compartment.