Search PubMed⌕ Search

Biomedical subjects

B Benson

Publications and source records attributed to B Benson.

At least 73 records · Page 4Linked to original sources
PubMed1984

An electrophoretic and immunochemical characterization of human surfactant-associated proteins.

We have prepared an antiserum against a serum-free extract of alveolar proteinosis lavage that recognizes the same proteins as an antiserum to human surfactant. Using one and two-dimensional gel electrophoresis, protein blotting and immunostaining we have found proteins with Mr of approx. 35 and 60 kDa to be present in every source of human surfactant we have examined. These proteins are immunologically related to those found in the lavage from alveolar proteinosis patients, have the same electrophoretic characteristics and are not found in serum. The 35 kDa protein is a group of at least eight isoforms ranging in relative molecular mass Mr from 32 to 36 kDa with isoelectric points between 4.8 and 5.5. Neuraminidase digestion studies have shown that at least part of this charge heterogeneity may be due to sialic acid residues. The less abundant form, with a Mr of about 60 kDa is also a sialoglycoprotein with similar isoelectric points.

Amniotic Fluid↗
PubMed1982

A study of the relationship between photoperiod and pinealocyte granulated vesicles in the golden Syrian hamster.

Previous studies in rabbits and mice have revealed distinct circadian rhythms in the number of pinealocyte granulated vesicles (PGVs) and control of their synthesis and/or secretion by sympathetic nerves. The present study demonstrates the absence of a circadian rhythm in PGV content in hamsters "functionally pinealectomized" by maintenance under long photoperiod (L/D = 14/10 h). On the other hand, a highly significant rhythm of low amplitude was noted in PGVs of hamsters placed in photoperiods (less than 12.5 h) which are known to initiate pineal antigonadotropic activity. Bilateral optic enucleation, which also leads to pineal-mediated gonadal atrophy in the hamster, produced a significant decrease in the number of perivascular PGVs when compared to intact control animals. Daily late afternoon injections of melatonin produced no significant difference in the number of PGVs between treated and control animals at any sample time examined.

Animals↗
PubMed1982

Preliminary results--isolation and identification of pineal neurohypophysial hormone-like activity.

We have initiated a project designed to isolate and identify the neurohypophysial peptides found in the bovine pineal gland. Our principle interest is to provide definitive molecular evidence in order to eliminate the conflict created by the present literature as to the presence of arginine vasotocin in the mammalian pineal gland. The pineals were extracted and chromatographed according to standard methods for the isolation of neurohypophysial peptides. All fractions were assayed for their ability to cause milk ejection using the in vivo assay described by Hadley et al. (1975). However, during the course of the isolation procedure a partially purified fraction was isolated that showed neurohypophysial hormone-like activity. According to tests run on parallel chromatographic columns, the substance responsible for the neurohypophysial hormone-like activity could not be oxytocin, arginine vasotocin or arginine vasopressin.

Animals↗
PubMed1980

Biosynthesis of taurine by rat pineals in vitro.

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. However, when subjected to one or two dimensional paper chromatography especially the eluants from pineal gland extracts yielded two 14C-labeled substances one located in the region where unlabeled taurine is detected by ortho-phthalaldehyde reagent. These results were confirmed utilizing a method developed in our laboratory based on high performance liquid chromatography (HPLC). The pineals, as well as their respective incubation medium, were shown to contain radioactive taurine. These results demonstrate that rat pineal glands are capable of taurine synthesis. Also a high degree of labeling was associated with an area on paper chromatograms, migrating more rapidly than the standards, using acidic solvent systems. If represented by a single pineal compound, the substance must be rapidly synthesized from 14C-cystine to account for the radioactivity observed. Future studies of sulfur metabolism within the pineal gland could be of significant interest.

Animals↗
PubMed1980

Continued chemical and physiological studies with antigonadotropic fractions from extracts of bovine pineal glands.

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.

Animals↗
PubMed1980

Relationship among reproductive variables, sucrose taste reactivity and feeding behavior in humans.

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. The data were analyzed by gender, length of menses, and phase of the menstrual cycle. The results of these analyses were consistent for both the sucrose taste reactivity tests and feeding tests. Male and long-menses females exhibited similar response patterns; and their pattern was significantly different from that of the short-menses females. The mean log pleasantness ratings of the males and long-menses females were significantly smaller than those of the short-menses females. Furthermore, both long-menses females and males behaved similarly in a time-limited surreptitious feeding test. They consumed significantly more food than did short-menses females. Phase of the menstrual cycle did not alter pleasantness reponse patterns, but there was one phase effect in the feeding tests. Luteal phase intake of short-menses females was elevated relative to that of the menses phase. These findings demonstrate that reproductive variables participate in the control of human regulatory behaviors.

Adolescent↗
PubMed1980

Possible role of prolactin and pineal prolactin-regulating substances in pineal-mediated gonadal atrophy in hamsters.

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. Prolactin, but not LH, levels were maintained in hypophysectomized male hamsters bearing pituitary homografts. These results point out the significant role played by prolactin, and possibly that of pineal prolactin-regulating factors, in pineal-mediated gonadal atrophy.

Animals↗
PubMed1979

Effects of reserpine and p-chlorophenylalanine on the circadian rhythm of granulated vesicles in the pinealocytes of mice.

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. Mice were housed in an environmental chamber under controlled lighting (12L/12D), and were treated with either reserpine, a drug which depletes serotonin and norepinephrine, or p-chlorophenylalanine (p-CPA), an inhibitor of serotonin synthesis. They were sacrificed at various times over a twenty-four hour period, and granulated vesicles present in the pinealocytes were quantitated in thin cross sections through pericapillary areas. Reserpine treatment resulted in a marked increase in the number of granulated vesicles during the dark, but led to a slight decrease during the photoperiod. Treatment with p-CPA produced no significant effect. The results of this study do not support our previous theory that melatonin plays an important role in the regulation of the pinealocyte secretory process, but instead points more directly to the significant role that norepinephrine has in controlling pinealocyte secretion.

Animals↗
PubMed1979

Location by paper chromatography of compensatory ovarian hypertrophy (COH) inhibiting activity in isobutanol extracts of bovine pineals.

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. With the Bensinger method, different active pineal fractions were obtained from Sephadex G-15 columns. Certain of those fractions were further separated by paper chromatography in butanol : acetic acid : water (4 : 1 : 1) and the COH-inhibitor was localized. The pineal COH-inhibitor could also be localized by high pressure, reverse phase liquid chromatography. More COH-inhibiting activity was extracted with the Bensinger method than with aqueous and acetic acid extraction methods used earlier by us. The Cheesman extraction method for arginine vasotocin gave less regular results in our hands than the Bensinger extraction method.

Animals↗
PubMed1979

Preliminary characterization of bovine pineal prolactin releasing (PPRF) and release-inhibiting factors (PPIF) activity.

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. PPRF activity was present in certain fractions derived from Sephadex G-25 and in the PM10 residue (MW congruent to less than 10,000). Whereas both the UM2 residue (MW greater than 1000) and UM05 filtrates (MW less than 500) was seen to inhibit pituitary prolactin release in vitro, the UM05 residue (MW greater than 500 and less than 1000) inhibited prolactin release in vivo, possibly by stimulating the secretion of the hypothalamic prolactin inhibiting factor. On the basis of its inactivation by trypsin it was concluded that PPIF may be a peptide or contain a peptide moiety indispensible for its biological activity. Experiments are in progress to characterize pineal prolactin-regulating activities and to elucidate further the physiological role of the pineal gland in the regulation of prolactin secretion.

Animals↗
PubMed1979

Localization and chemical characterization of a partially purified bovine pineal antigonadotropin.

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. The partially purified antigonadotropin was characterized chemically using techniques of UV and fluorescence spectrometry, thin layer and paper chromatography, paper electrophoresis and amino acid analysis. The results reveal a diversity of ninhydrin-positive components present in the preparations, including free and peptide-bound amino acids, as well as other unidentified components, but not including any of the commonly occurring indoles, indoleamines or catecholeamines. One peptide, oxidized glutathione, was identified in the most purified material containing the biologically active principle yet pure, synthetric glutathione has no antigonadotropic activity in the biological tests utilized. Although the chemical nature of the bovine pineal antigonadotropin remains in question it may be purified by the methods described. The activity is thought to reside in the extremely small, perhaps trace quantities of residues derived. It is believed that large scale, preparative studies will be required for structural determination.

Amino Acids↗