Hyaluronidase activity and hyaluronate content of the developing chick embryo heart.

Hyaluronidase activity and hyaluronate content were measured in the developing chick heart from embryonic day 3 through posthatching stages. High levels of both enzyme and substrate were found during the earliest stages examined. Hyaluronidase activity gradually declined to 63% of the initial (day 3) level by embryonic day 16. Enzyme activity decreased more sharply during the next 4 days to 30% of the initial level and remained constant through 2 weeks after hatching. Low levels of enzyme activity (about 10% initial levels) were still detectable in 10-week-old chicken hearts. The heart hyaluronidase is an endoglycosidase with an estimated molecular weight of 62,000, which degrades hyaluronate and, to a lesser extent, chondroitin sulfate at an acid pH optimum. Hyaluronate constituted approximately 50% of the total glycosaminoglycan content at embryonic day 5. Between embryonic days 5 and 12, the concentration of hyaluronate decreased to 25–30% of the initial level and remained constant thereafter. The level of other glycosaminoglycans decreased more gradually than hyaluronate and did not reach a constant level until hatching. This pattern of hyaluronidase activity and hyaluronate concentration presumably reflects the extensive tissue remodeling which transforms the developing heart from a thin-walled tube containing extensive regions of extracellular matrix to a compact, thick-walled myocardium having a limited extracellular compartment.     

The preservation of Mullerian inhibiting substance during long-term freezing of testicular fragments

Mullerian Inhibiting Substance, a fetal testicular hormone found in most mammalian species, causes regression in the male of the Mullerian duct, the anlagen of the fallopian tube, uterus, and upper vagina. Limitations to study of this substance in the past have been posed by its short period of production and by its localized and specific action. We have been able to store testicular fragments that continue to demonstrate detectable Mullerian Inhibiting Substance activity for up to 5 months by using techniques of slow freezing which approximate 1 °C/min, cryoprotective additives, storage in liquid nitrogen, and rapid thawing. These fragments then can be pooled for biochemical and endocrinological studies. In addition, unknown fragments can be transported long distances for assay of Mullerian Inhibiting Substance.     

Patterns of cell polarity in the developing mouse limb

Most cells have a morphological polarity with the centrioles and Golgi apparatus occupying one pole of the cell and the nucleus the other. This structural polarity often correlates with functional polarity as in secretory epithelia where the Golgi apparatus moves to the pole of the cell from which secretory materials are exreted. In limb development an interaction of unknown mechanism occurs between the epithelium and mesenchyme. We have evaluated the pattern of cell polarity using silver impregnation of the Golgi apparatus in limb epithelium and mesenchyme of mouse embryos from day 9.5, when limbs are first visible, to day 15, when cartilage formation is complete. Cells in the epithelium almost always have the Golgi apparatus in the apex of the cell, i.e., oriented away from the basement membrane. The layer of mesenchyme cells just beneath the basement membrane initially has only 16 to 25% of the cells oriented toward the basement membrane. A marked shift in orientation occurs between days 12 and 13 so that from days 13 to 15 up to 53% of the mesenchyme cells are oriented toward the basement membrane. This shift in orientation occurs more slowly in the mesenchyme at a depth of four cells below the basement membrane. This changing pattern of mesenchymal cell polarity occurs at a time when there is an apparent increase in the amount of extracellular matrix, especially in the region just below the basement membrane.     

Inhibition of an IUD-induced precocious luteolysis by prostaglandin E1 (PGE1) in sheep

Fifteen ewes were assigned as they came into estrus to one of three randomized treatment groups: 1. Sham IUD + Vehicle, 2. IUD + Vehicle or 3. IUD + PGE₁ in vehicle. An IUD was inserted adjacent to the luteal-bearing ovary on day 3 postestrus. Prostaglandin E₁ (500 μg) in vehicle (Na₂CO₃) or vehicle was given intrauterine through an indwelling uterine cannula every four hours from day 3 postestrus until ewes returned to estrus. Precocious estrus was induced in both the sham IUD groups receiving vehicle. Prostaglandin E₁ prevented an IUD-induced premature luteolysis based on daily concentrations of progesterone in peripheral blood and the interestrous interval. It is concluded that an IUD-induced premature luteolysis is not necessarily via physical distention by the IUD. It is also concluded that chronic intrauterine infusions of PGE₁ can prevent an IUD-induced premature luteolysis.     

Interactions of prostaglandin E1 (PGE1) and LRH on anterior pituitary function

Numerous biochemical pathways influence the synthesis and release of anterior pituitary hormones. Releasing factors extracted from the hypothalamus and prostaglandins (PGs) appear to alter a common biochemical activity, adenyl cyclase, in pituitary cells. Luteinizing hormone releasing hormone (LRH), prostaglandin (PGE₁), 7 oxa-13-prostynoic acid and cycloheximide were tested for individual and interacting effects on the in vitro release of FSH, LH and prolactin from hemipituitaries of 15 day old female rats. LRH (10 ng/ml) consistently released both LH and FSH in all in vitro experiments and inhibited prolactin release in 1 of 2 experiments. Lower concentrations (5 and 1 ng/ml) also stimulated LH and FSH release but did not influence prolactin release. Concurrent depletion of stored LH and FSH in the gland was observed. PGE₁ in a 6.5 hour incubation increased the storage of LH within the gland in the absence of LRH. In a 1.5 hour incubation in the presence of LRH, storage of LH was also increased. PGE₁ had no effect on LH and FSH release; however, in 1 of 2 experiments it stimulated prolactin release in the absence of LRH. Prostynoic acid stimulated LH and FSH release but did not synergize with LRH action in the same tissue. Cycloheximide did not affect LH release during the first 30 minutes of incubation; however, the release during the subsequent 1 hour was significantly inhibited. Similar tissue also exposed to cycloheximide was still responsive to LRH during the latter 1 hour incubation period. Cycloheximide had no effect on prolactin storage and release from the same tissue.     

Cell polarity in precartilage mouse limb mesenchyme cells

The patterns of orientation of individual mesenchyme cells have been evaluated in the hindlimb of the mouse embryo during the period of transition from early aggregation (Day 12) to cartilage formation (Day 13). Orientation was measured by determining the angular relationship between the Golgi-nucleus axis of each cell relative to either the longitudinal limb axis or the center of the cartilaginous aggregate. Patterns were assessed qualitatively and quantitatively in horizontal, vertical, and transverse sections of the proximal, middle, and distal precartilage mesenchyme. These analyses showed that the mesenchyme cells are oriented predominantly toward the longitudinal axes of both the early (Day 12) and late (Day 13) aggregates.     

Urinary excretion of prostaglandin E2 and prostaglandin F2α in potassium-deficient rats

Potassium-deficiency was induced in rats by dietary deprivation of potassium. The animals became polyuric and urine osmolality decreased more then three-fold compared to controls. Urinary excretion of prostaglandin E₂ (PGE₂) and prostaglandin F_2α (PGF_2α) did not increase during 2 weeks of potassium depletion. Partial inhibition of renal prostaglandin synthesis by meclofenamate did not increase the urine osmolality after water deprivation. These results make unlikely the hypothesis that the polyuria of potassium-deficiency, is the result of enhanced renal synthesis of prostaglandins with subsequent antagonism of the hydro-osmotic effect of vasopressin. Male animals consistently excreted less PGE₂ than female animals.     

Helper factor(s) augment in vitro induction of tumor-specific immunity

Helper factor supernatants derived from alloantigen-activated murine lymphocytes augment the generation of cytolytic effector cells to syngeneic tumor cells. The effects are dose dependent and vary with the syngeneic tumor cell system studied. The effector cells are specific for the tumor-associated antigen(s) utilized for their induction, and are sensitive to lysis with anti-T-cell serum (Thy 1.2), but are insensitive to lysis with an allogeneic anti-NK-cell serum. The helper factor supernatants also augment the production of a “tissue-culture-induced” cytolytic cell (cultured NK cell), which is resistant to treatment with both anti-Thy 1.2 and anti-NK serum.     

Ly-4.2: a cell membrane alloantigen of murine B lymphocytes. III. In vitro studies

The alloantigenic specificity Ly-4.2 is present on a restricted population of murine lymphocytes which have previously been shown to have some of the properties generally ascribed to B lymphocytes, both with regard to distribution and function. In the study reported herein, the effect of anti-Ly-4.2 and anti-Thy-1.2 (θ) antisera have been examined in various in vitro systems. (a) T cell-mediated lysis of ⁵¹Cr-labeled P815-X2 target cells by immune allogeneic peritoneal exudate cells is inhibited by anti-Thy-1.2, but not affected by the anti-B (Ly-4.2) reagent. (b) Antibody-dependent lymphocyte-mediated lysis of ⁵¹Cr-labeled sheep red cells was only slightly inhibited by anti-Ly-4.2 and anti-Ig antisera, and not at all by anti-Thy-1.2 antisera, indicating that this type of cell lysis is mediated by neither T (Thy-l⁺) nor B (Ly-4.2⁺,Ig⁺) cells. (c) The response of lymph node lymphocytes to various mitogens was affected thus: PHA, completely inhibited by anti-Thy-1.2 but not by anti-Ly-4.2; Con A, largely inhibited by anti-Thy-1.2, and slightly by anti-Ly-4.2; PWM (pokeweed mitogen), partially inhibited by both antisera; E. coli endotoxin lipopolysaccharide, greatly inhibited by anti-Ly-4.2 but only slightly by anti-Thy-1.2. The findings demonstrate that anti-Thy-1.2 reacts predominantly with T cells and anti-Ly-4.2 with B cells.     

Bronchodilatory properties of 2-decarboxy-2-hydroxymethyl prostaglandin E1

We evaluated in a double-blind study the bronchodilatory properties of 2-decarboxy-2-hydroxymethyl prostaglandin E₁ (PGE₁-carbinol), described recently as a nonirritant bronchodilator in animals. Fifteen asthmatic patients received by inhalation single doses of 1, 10, and 30 μg PGE₁-carbinol, 55 μg PGE₂, and placebo (10% ethanol in normal saline, which was also used as diluent for the PGs). Such pulmonary function tests as forced expiratory volume in 1 second, forced vital capacity, and maximal expiratory flow were monitored during 2 hours following inhalation of each compound. 10 and 30 μg PGE₁-carbinol produced significant but short-acting bronchodilation, similar to that caused by 55 μg PGE₂. One-third of the patients reported mild cough and throat irritation during and shortly after inhalation of 30 μg PGE₁-carbinol or 55 μg PGE₂. Placebo and 1 μg PGE₁-carbinol produced minimal side effects, but neither agent caused bronchodilation. In an adjunctive, unblinded trial, the same patients received 400 μg fenoterol. Fenoterol caused greater bronchodilation 15 and 30 minutes after inhalation than did the PGs in the double-blind study.     

Effects of prostaglandin E2 (PGE2) on estradiol-17β-induced luteolysis in the nonpregnant ewe

Fifteen ewes were assigned as they came into estrus to the following randomized treatment groups: 1) Vehicle (1 ml corn oil + vehicle Na₂CO₃ buffer), 2) Estradiol-17β + vehicle and 3) Estradiol-17β + PGE₂ (500 μg) in Na₂CO₃ buffer (5 ewes/treatment group). Prostaglandin E₂ was given through an intrauterine cannula every four hours from days 8 through 15 postestrus. PGE₂ prevented a luteolytic dose of estradiol-17β given on days 9 and 10 from causing a precious luteolysis. PGE₂ maintained concentrations of progesterone in peripheral blood (days 8 through 15) and weights and concentrations of progesterone in corpora lutea on day 15 postestrus of ewes receiving estradiol-17β. It is concluded that chronic intrauterine infusions of PGE₂ can prevent an estradiol-17β-induced premature luteolysis.     

On the biochemical similarities of ascorbic acid and interferon

The anti-viral effects of ascorbic acid and interferon are proposed to result from the peroxy radical mediated biosynthesis of prostaglandins and from the direct attack of free radical species on unsaturated lipids in the cell membrane. These processes are proposed to lead to changes in fluidity of the host cell membrane which inhibit the fusogenicity of the attacking virus.     

The action of prostaglandin E2 and F1α on myocardial ischaemia-infarction arrhythmias in the dog

Prostaglandin E₂ and F_1α infusions have been tested for their ability to reduce the arrhythmias associated with occlusion of the left descending coronary artery in the anaesthetised dog. At 1 μg/kg/min both PGs reduced the incidence of premature ventricular contractions occurring during 25-min occlusions, while not reducing the incidence of ventricular fibrillation occurring on occlusion release. When infused for 5-min periods at 1 to 16 μg/kg/min, neither PGE₂ nor PGF_1α effectively reduced the frequency of ventricular arrhythmias occurring 24 hr after a permanent coronary occlusion.     

A new prostaglandin E1 analogue (CL115, 574): I. Antisecretory and cytoprotectige effects in the rat

The effect of a new analogue of PGE₁ (CL115, 574) on gastric acid secretion, mucus secretion and protection against stress and indomethacin- induced ulcers were studied in the rat. CL115, 574 was more potent than PGE₁ and cimetidine in inhibiting acid secretion. CL115, 574 protected against the development of stress and indomethacin-induced ulcers prevented the indomethacin-induced decrease in hematocrit at an ED₅₀ (3 μg/kg) far below the antisecretory ED₅₀ (1 mg/kg). While the inhibiting acid secretion, CL115, 574 increased the volume of gastric secretion indicating a stimulation of nonparallel cell secretion by the rat stomach. In addition the compound stimulated the secretion of mucus into the gastric juice. On the basis of its potency as an inhibitor of acid secretion and these additional effects which are indicative of cytoprotective activity, CL115, 574 should be further studied as a possible anti-ulcer agent in man.     

The sites of synthesis and the subsequent migration of newly synthesized protein in retina

Radioautographs of rabbit retinas fixed immediately after a 1 or 2 min exposure in vitro to ³H leucine revealed high rates of protein synthesis in receptor cell inner segments, perikarya of ganglion cells, and cells of the inner nuclear layer. If these brieflly labelled retinas were returned to unlabelled medium for periods of up to 6 hr, the radioautographs revealed a progressive dispersion of the labelled proteins from their sites of synthesis. This was largely completed by $\text{1}\text{1}\text{2}$ hr and appeared, in one instance at least, to involve processes other than simple diffusion. Superimposed on the dispersive phenomenon was a process of concentration of the newly formed proteins at two sites quite distant from their synthesis, that was apparent after $\text{1}\text{1}\text{2}$hr. One of these sites was the receptor cell outer segments, as has been previously described, the other was the outer plexiform layer.     

Neurological and electroencephalographic changes in newborns treated with prostaglandins E2 and E2

Six newborns with obstructive right heart lesions were examined neurologically and electroencephalographically during treatment with prostaglandin (PG) E₁ or E₂ given to maintain patency of the ductus arteriosus and to increase pulmonary blood flow. PG was administered intravenously or intraarterially in the aortic isthmus proximal to the ductus arteriosus. Besides a rise in arterial oxygen saturation, all patients had some sign of central nervous system involvement. The electroencephalogram showed minor changes suggestive of sedation. In addition, three patients in whom PG given intravenously presented various combinations of neurological abnormalities (“myoclonic jerks”, apnoeic spells, hiccup) of subcortical origin. Side-effects subsided after stopping the treatment anf posed no problem in the management of the patients. These findings confirm the usefulness and safety of the PG therapy and indicate that the intraaortic route of administration is preferable.     

Specificity of receptors for leukotrienes A4, B4, C4, D4, E4 and histamine on the guinea-pig lung parenchyma. Effect of FPL-55712 and desensitization of the myotropic activity

The novel metabolites of arachidonic acid, leukotriene (LT) A₄, B₄, C₄, D₄ and E₄ have potent myotropic activity on guinea-pig lung parenchymal strip . The receptors responsible for their action were characterized using desensitization experiments and the selective SRS-A antagonist, FPL-55712. During the continuous infusion of LTB₄, the tissues became desensitized to LTB₄ but were still responsive to histamine, LTA₄, LTC₄, LTD₄ and LTE₄. When LTD₄ was infused continuously, the lung strips contracted to LTB₄ and histamine but were no longer responsive to LTA₄, LTC₄, LTD₄ and LTE₄. Furthermore, FPL-55712 (10 ng ml⁻¹− 10 ug ml⁻¹) produced dose-dependent inhibitions of LTA₄, LTC₄, LTD₄ and LTE₄ without inhibiting the contraction to LTB₄ and histamine. On the basis of these results, it appears that the guinea-pig lung parenchyma may have one type of receptor for LTB₄ and another for LTD₄; LTA₄, LTC₄ and LTE₄ probably act on the LTD₄ receptor.     

Zymosan activated plasma infusion in sheep: Effects of ethanol administration

Zymosan activated plasma infusion induces pulmonary sequestration of neutrophils and the release of TXA₂ into the pulmonary vascular bed causing profound and transient pulmonary hypertension.Since ethanol (ETOH) inhibits several inflammatory functions of neutrophils, including adherence and aggregation, we examined the ability of anesthetic doses of ETOH to alter the hemodynamic and cellular response to the infusion of zymosan activated plasma (ZAP) in vivo. Twenty five ml of autologous ZAP was intravenously infused into five control and seven (ETOH-treated sheep during mechanical ventillation. In control sheep the mean pulmonary artery pressure (PAP) transiently increased from 14.7±1.4 mm Hg (mean±SEM) to a pead of 38+8 mm Hg by three minutes after beginning the infusion of ZAP. Blood leukocyte concentration transiently decreased 19% below the baseline value due to pulmonary sequestration of polymorphonuclear leukocytes (PMN). Plasma TXB₂ levels measured by radioimmunoassay (RIA) increased from 0.2 to 5.4 ng/ml six minutes after the initiation of ZAP infusion.In five sheep, intravenous infusion of 200 ml of 96% ETOH yielded very high plasma concentrations (882±101 mg%) and completely inhibited both the rise of PAP and the increase of plasma TXB₂ levels after ZAP infusion. However, blood leukocytes transiently decreased 58% below the baseline value. Lower plasma levels of ETOH (200 and 400 mg%) did not prevent either the increase of PAP or the elevation of plasma TXB₂ after ZAP infusion.     

Separation of mitogen-induced suppressor cells of human antibody-producing cells

Human antibody-forming cells were demonstrated by a plaque in agar technique following in vitro stimulation with either pokeweed mitogen or Cowan I strain of protein A-positive Staphylococcus aureus bacteria. We evaluated the effects on this antibody formation caused by the addition of cells which had been stimulated with PH A or Con A. Both Con A and PHA cells harvested after 3 days showed strong inhibition of pokeweed-induced plaque formation. The majority of the suppression could be accounted for by a blast fraction separated on 1g sedimentation gradients from the Con A or PHA cultures. Small cells from such cultures showed inhibition of PFC when added at high ratios (1:2), but this suppressive activity diluted out much more rapidly than that of the blast cells. No helper activity was noted with either small cells or blasts. Our studies indicate a T-cell blast as the suppressive fraction in Con A- or PHA-stimulated human lymphoid cells. While this T-cell suppression applies to T-dependent responses such as antibody stimulation with pokeweed mitogen, it does not have a substantial effect on Cowan I-induced plaque-forming responses. The finding that Cowan I-induced plaques could not be inhibited by Con A or PHA blasts indicates the T independence of this response.