Publications by authors named "Benson B"

We studied some of the biochemical and immunochemical properties of a major apolipoprotein in isolated pulmonary surfactant from dog and rat lungs. These apolipoproteins were purified by DEAE-cellulose chromatography in buffers containing Triton X-100. Purity of the apolipoproteins was assessed by both fused rocket and crossed immunoelectrophoreses.

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We investigated the cellular and subcellular sites of metabolism of the 72,000 dalton protein of pulmonary surfactant in order to provide insights into mechanisms of synthesis, intracellular assembly, and intraalveolar metabolism of this phospholipid-rich secretory product. Surfactant (approximately 90% lipid, 10% protein by weight) was purified by density gradient centrifugation of material obtained by lavaging rat lungs. The purified material was used to generate an antiserum from which a specific antibody was obtained by affinity chromatography.

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Pulmonary surface active material (SAM), purified from canine lung lavage fluids, is a phospholipid-rich lipoprotein with potent immunosuppressive activity. Experiments were performed to identify those components of SAM that were responsible for this immunosuppressive effect. Results indicated that the lipid, and not the protein, fraction of SAM was immunosuppressive.

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Magnitude-estimation of sucrose pleasantness and sweetness, and feeding behavior, were investigated in female and male college students. The subjects were individually tested five times over a five-week period. Female test intervals were scheduled to include the menses, pre-ovulatory, and luteal phases of the menstrual cycle.

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The effect of thyroid hormone on maturation of fetal rabbit lung was studied with maternal treatment using 3,5-dimethyl-3'-isopropyl-L-thyronine (DIMIT), a synthetic analogue of triiodothyronine. To investigate the in vivo kinetics and distribution of DIMIT, we prepared [3H]DIMIT and injected both pregnant rats (18-21 d gestation) and rabbits (25 d gestation). In the rat, maximal concentrations of radioactivity in maternal plasma, fetal plasma, and amniotic fluid occurred within 10 min, 1-2 h, and 4-6 h, respectively, after intramuscular injection.

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Canine bronchoalveolar cells, obtained by lavage, were enriched for lymphocytes by adsorption to plastic or by filtration over nylon wool and tested for their ability to function in the mixed lymphocyte culture (MLC) reaction. Pulmonary lymphocytes were markedly hyporesponsive to stimulation with allogeneic cells in vitro: their responses rarely exceeded 10% of those of blood lymphocytes obtained simultaneously from the same donor. However, pulmonary lymphocytes did function as stimulating cells, inducing allogeneic blood lymphocytes to proliferate in MLC.

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Lung surfactant, a lipid-protein complex purified from dog lungs, contains a highly active phosphomonoesterase associated with it. This phosphatase is quite specific for the hydrolysis of phosphatidic acid and 1-acyl-2-lysophosphatidic acid. The enzyme possesses many of the characteristics of the microsomal enzyme, phosphatidate phosphohydrolase (EC 3.

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Pineal glands from adult, male rats were incubated in oxygenated Krebs-Ringer buffer containing 14C-cystine. After three hours the incubation media and pineal gland extracts were placed separately on Dowex AG W50-X-4 columns. In the elution volume where 14C-labeled taurine is found a labeled peak was recovered.

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A variety of experiments carried out in recent years are reviewed and evidence is presented for the presence of non-indolic, pineal antigonadotropic substances in pineal extracts and partially purified pineal fractions. Other data are presented suggesting the presence of prolactin releasing and release-inhibiting substances in bovine pineal glands. Also, the sulfur-containing amino acid and putative neurotransmitter taurine was found in large quantities in bovine pineals closely associated with fractions possessing antigonadotropic activity.

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Homoplastic anterior pituitaries were transplanted beneath the renal capsule of adult male, Syrian golden hamsters and the effects studied on the gonadal and accessory organ atrophy following bilateral optic enucleation or placement in reduced (L/D = 10/14 h) photoperiods. In all cases, control hamsters, bearing kidney fragments transplanted beneath their renal capsules, showed gonadal atrophy and reduced blood levels of prolactin and LH at 8--10 weeks following light deprivation. On the other hand, hamsters, bearing three or four homoplastic pituitary grafts, showed complete maintenance of gonadal and accessory weights as well as normal or supranormal serum prolactin levels.

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Surface-active material isolated from the lungs of both dogs and rats was tested for its ability to suppress the in vitro proliferative responses of dog, mouse, or human lymphocytes to a variety of immunologic stimuli. Both dog and rat surface-active material exerted a dose-dependent suppressive effect on the proliferative responses of each species of lymphocyte, regardless of the nature of the immune stimulus (mitogen, antigen, or alloantigen). The data indicated that surface-active material acts by directly inhibiting the responding lymphocyte and not by activating suppessor cells.

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The effect of taurine on calcium binding to isolated rat heart sarcolemmal membrane was examined. Taurine was observed to increase calcium binding to the low affinity sites in both high sodium-low potassium and low sodium-high potassium buffers. Taurine was also seen to antagonize the inhibition of calcium binding to the sarcolemma caused by both verapamil and lanthanum.

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An antigonadotropic substance was partially purified from aqueous extracts of bovine pineal glands by methods of gel filtration, ultrafiltration and ion exchange chromatography. Two biological tests, viz. inhibition of compensatory ovarian hypertrophy and reduction of ventral prostate weight, were used to guide the purification.

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Bovine pineal glands were extracted according to the methods reported by Bensinger et al. (1973) and Cheesman and Fariss (1970). Isobutanol soluble COH-inhibiting activity was further separated by chromatography on Sephadex G-15 and paper chromatography.

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The number of granulated vesicles in mouse pinealocytes exhibit a distinct circadian rhythm which is abolished by superior cervical ganglionectomy. Since melatonin treatment markedly effects the number of pinealocytic granulated vesicles, it was suggested that a relationship may exist between norepinephrine, melatonin, and the synthesis and/or secretion of pinealocyte granulated vesicles. The present study was undertaken in an attempt to clarify this relationship.

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Bovine pineal glands were subjected to extraction with dilute acetic acid, gel filtration on Sephadex G-25 and subsequent ultrafiltration through Diaflo membranes PM10, UM2 and UM05. Various fractions derived at each step were tested for the presence of substances which stimulate or inhibit prolactin secretion in vitro and in vivo. Both prolactin releasing (PPRF) and release-inhibiting (PPIF) activities were observed.

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Acetic acid extracts of bovine pineals and cerebral cortex were separated on Sephadex G-25 columns. Subsequently two low molecular weight fractions, F2 and F3, were ultrafiltered through the membranes UM2 and UM05. The UM05 residues were gel filtered on Sephadex G-15 columns or chromatographed on Dowex W50-X4 columns.

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