Calcium adenosine triphosphatase and secretion of koilin membrane in the gizzard of the fowl.

The localization of calcium adenosine triphosphatase (Ca(2+)-ATPase) was determined histo- and ultracytochemically in the gizzard gland cells of the adult domestic fowl. Surface and chief gland cells exhibited faint and inconstant basolateral activity in contrast to basal cells, whose basolateral cell membrane constantly showed deposition on the external side. Intracellular enzyme activity was localized on the luminal aspect of Golgi membranes in all types of gland cells. Lysosomes also reacted positive for Ca(2+)-ATPase. Neither membranes of secretory vesicles nor cortical cytoplasm of the secretory pole exhibited enzyme activity. From these results it is speculated that calcium is not essentially involved in the secretion of the koilin membrane in terms of storage of the secretory material, transport to the secretory surface and release into the lumen. Ca(2+)-ATPase activity rather seems to be related to differentiation and maturation processes and to intracellular storage of Ca2+.     

Formation of 15-lipoxygenase product from docosahexaenoic acid (22:6w3) by human platelets

The metabolism of docosahexaenoic acid (22:6w3) by 15-lipoxygenase activity of washed human platelets was investigated. Platelets produced 17-hydroxydocosahexaenoic acid (HDHE) when incubated with 22:6w3. Similarly, 15-hydroxyeicosatetraenoic acid (HETE) and 13- and 9-hydroxyoctadecadienoic acids (HODD) were produced when incubated with 20:4w6 and 18:2w6, respectively. However, these products were observed only as minor components in the platelet incubation mixture. Control studies with carefully purified platelets and mononuclear cells indicated that these products were formed by the platelets. Chiral phase HPLC analysis indicated that these compounds were mainly in the S configuration with the exception of the 9-HODD, thus, confirming that a lipoxygenase is responsible for their production. The 9-HODD produced by platelets was a racemic mixture.     

Ca2+-ATPase in mucous and oxyntico-peptic cells of the fowl proventriculus

Summary Calcium adenosine triphosphatase (Ca²⁺-ATPase) was localized by means of histo- and ultracytochemistry in the secretory cells of the proventriculus of the domestic fowl. The mucous cells exhibited plasmalemmal-associated enzyme activity on the external aspect of the basolateral cell membrane. Intracellularly, the luminal aspect of Golgi-membranes and of secretory vesicle membranes reacted positively for Ca²⁺-ATPase activity, as did the apical cytosol and the matrix of lysosomes. Oxyntico-peptic cells were characterized by apical and apico-lateral plasmalemmal activity and by an organelle-associated distributional pattern similar to that in the mucous cells. In addition, Ca²⁺-ATPase was associated either with the matrix of mitochondria or with tubuli of the rough-surfaced endoplasmic reticulum. The results are discussed with respect to messenger and effector functions of calcium in the process of proventricular mucus secretion. In addition, Ca²⁺-ATPase distributional patterns in the oxyntico-peptic cell are related to the unique structure and function of these cells.     

Lipoxygenation in rat brain?

It has been previously claimed that rodent brain possesses lipoxygenase activity, based upon the structure of products which were formed from arachidonic acid and the inhibition of this activity by "lipoxygenase inhibitors." Our studies confirm that various positional isomers of hydroxyeicosatetraenoic acids (HETE) are formed (e.g., 15-, 12-, 11-, 9-, 8- and 5-HETE) by brain homogenate and that their production is inhibited by certain lipoxygenase inhibitors, such as nordihydroguaiaretic acid (NDGA) but not by cyclooxygenase or cytochrome P-450 inhibitors. However, stereochemical analysis indicated racemic distributions of these products suggesting that they were not formed by a lipoxygenase enzyme but rather by a peroxidative process. It should also be noted that the presence of 12(S)-lipoxygenase activity could be demonstrated by stereochemical analysis only when the brain was not perfused properly, indicating this activity was due to blood cell contamination. It is known that many lipoxygenase inhibitors are also capable of inhibiting peroxidative reactions apparently due to their free radical scavenging properties. For these reasons, it is essential that the stereochemical purity of purported lipoxygenase products be determined and that previous claims of lipoxygenase activity in mammalian brain be reexamined.     

The inhibitory effect of PGE2 on T cell activation is not associated with inhibition of PKC translocation

We have recently reported on the effect of PGE2 on T cell activation and suggested that their immunosuppressive effect may involve the PKC activation pathway. In the present study, we further investigated the potential interference of PGE2 with PHA induced signaling in T lymphocytes. We demonstrate that the PHA mediated increase in IP3, the putative mobilizer of intracellular Ca2+, is slightly affected following cell incubation with PGE2. Treatment of cell culture with the tumor promoter TPA abrogates the suppressive activity of PGE2 whereas exogenous diacylglycerol (1,2-diolein) has only a marginal effect. This suggests that PGE2 affect PKC activity at sites distal to IP3 and DG generation. We also demonstrate that the PGE2 suppressive effect on T lymphocyte activation is not related to an inhibition of PKC translocation.     

Synthesis of paf-acether from exogenous precursors by the prokaryote Escherichia coli

Paf-acether (paf) is a potent mediator of inflammatory diseases and septic shock. Using normal-phase HPLC, a paf-like activity was found in culture supernatants from E. coli. Prokaryotic paf exhibited the same biological and physico-chemical properties as eukaryotic cells and synthetic paf. Further, reverse-phase HPLC indicates that paf generated by bacteria is predominantly of the hexadecyl and octadecyl species. When cultures were supplemented with lyso-paf, a dramatic increase in paf production was observed. The purity and molecular structure of bacterial paf were further characterized by mass spectral analysis. These results could be of importance considering the pathogenetic role of enterobacteria. Further, it appears that the competence to form and release paf is an early phylogenetic development.     

The growth factor from plerocercoid larvae of the tapeworm, Spirometra mansonoides, stimulates growth but is not diabetogenic

A factor produced by plerocercoids of the tapeworm Spirometra mansonoides is similar to human growth hormone (hGH) in that it stimulates body growth, binds to hGH receptors, cross-reacts with anti-hGH antibodies, and has lactogenic and insulin-like activities. The purpose of this study was to determine whether plerocercoid growth factor (PGF) is similar to hGH in expressing diabetogenic activity in the genetically obese (ob/ob) mouse. To determine an effective dose for use in the obese mice, the ability of daily injections of PGF to stimulate growth of phenotypically normal mice of the same strain was assessed in a 10-day weight gain assay. Injections of PGF stimulated a dose-dependent weight gain (r = 0.83) and 25 ng eq/day of PGF stimulated a response not significantly different from that produced by 100 micrograms of bovine growth hormone/day. Diabetogenicity was assessed using fasting blood glucose and glucose tolerance tests in obese mice that had been injected for 3 days with saline, hGH, or PGF. Human growth hormone caused a significant increase (P less than 0.005) in fasting blood glucose and glucose tolerance of the obese mice was impaired (P less than 0.01). All of the doses of PGF used to test diabetogenicity in the obese mice were at least twice that required to stimulate a maximal growth response in normal mice, yet none of the doses of PGF increased fasting blood glucose or decreased glucose tolerance. These results show that PGF was a potent growth stimulant but was not diabetogenic.     

Effect of cyclic AMP, imidazole and triiodothyronine on the rate of RNA synthesis by ejaculated ram spermatozoa

The effects of cyclic AMP (cAMP) and of triiodothyronine (T(3)) on the enhancement of sperm motility and metabolism are well documented, and the present study was undertaken to investigate the mechanisms underlying these effects in terms of their influence on sperm RNA synthesis in vitro. Washed ram sperm were diluted to 1 40 (v/v) with incubation buffer that contained 100 mug/ml penicillin-G and 400 mg% glucose, followed by incubation at 37 degrees C for a period of 4 h. Washed ram spermatozoa incubated with graded doses of cAMP (10(-8), 10(-6) and 10(-4) M) showed significant enhancements of the rate of (3)H-uridine incorporation into RNA, with maximal effect occurring at 10(-8) M. The presence of 3.75, 7.50 or 15.00 muM T(3) also stimulated the rate of RNA synthesis by the washed ram sperm, with maximal effect occurring at 7.50 muM. On the contrary, imidazole (a compound known to stimulate phosphodiesterase activity and consequently to decrease the intracellular cAMP levels in many tissues) was found to cause consistent inhibition of spermatozoal RNA synthesis. The inhibition was 47, 90 and 92% of control for 10, 50 and 100 mM imidazole, respectively. The results obtained indicate that cAMP may act either as a first or a second messenger in the mature sperm. The data also indicate that T(3) (possibly mediated by cAMP) may act on the ram sperm by the induction of enzymes, which are required for the well-known effects of this hormone in enhancing the sperm metabolic activity.     

Intra-abdominal desmoplastic small round cell tumor

BACKGROUND: Intra-abdominal desmoplastic small round cell tumor is a rare malignancy with a predilection for young males. Unique histological and immunocytochemical features distinguish the tumor from other members of the family of small round cell tumors of infancy and childhood. The aggressive nature of tumor spread, relative insensitivity to chemotherapy, and generally incomplete resectability result in a very poor prognosis. The authors report a case of a 39-year-old man with diffuse abdominal and pelvic involvement of intra-abdominal desmoplastic small round cell tumor treated with aggressive chemotherapy and surgery. METHODS: Computed-tomography (CT)-guided biopsy of an omental mass was performed. Histologically, discrete nests of uniform closely packed malignant cells were distributed in a background of focally desmoplastic stroma. Immunocchemistry demonstrated positivity for epithelial, mesenchymal, and neural markers. On the basis of these unique histological and immunohistochemical characteristics, the diagnosis of desmoplastic small round cell tumor was made. The patient was treated with aggressive neoadjuvant chemotherapy consisting of a high-dose alkylator -based combination regimen, followed by surgery. RESULTS: The patient had a 10 to 15 percent regression in tumor mass in response to chemotherapy. Laparotomy revealed two large omental masses, another large mass adherent to the left colon and pelvic sidewall, and diaphragmatic, peritoneal and mesenteric studding with small nodules. Complete surgical resection was not possible. CONCLUSIONS: Intra-abdominal desmoplastic small round cell tumor remains an aggressive malignancy with an extremely poor prognosis. Although some response to chemotherapy may be possible, complete resection is rare, and surgical efforts are general palliative.     

Green micellar spectrofluorimetric determination of α-mangostin found in herbal products as antioxidant and other biological activities beneficial to human health

Pharmaceutical product quality control (QC) needs quick, sensitive and economical procedures to deliver high throughput at low cost, which is the key factor considered by such economic facilities. To lessen the risky effects of research laboratories, researchers must take into account the ecological impacts. α-Mangostin (MAG) exhibit anti-inflammatory, antioxidant, anticancer, anti-allergic, antibacterial, antifungal, antiviral and antimalarial activities. Based on the spectrofluorimetric approach, a novel straightforward, sensitive and environmentally friendly method for MAG determination was developed and validated. Many variables were investigated to improve MAG native fluorescence, including solvent type, buffers, pH and additional surfactants. The best MAG fluorescence sensitivity was found in Britton–Robinson buffer (pH 4) at 450 nm after irradiation at 350 nm in the concentration range of 5–50 ng ml⁻¹. The technique was successfully used to determine the presence of MAG in both its approved dose forms and in samples of spiked human plasma, as per FDA standards for validation. According to their evaluation on two recent greenness criteria (GAPI [Green Analytical Procedure Index] and AGREE [Analytical GREEnness]), the suggested approach has been shown to be environmentally beneficial because it normally uses biodegradable chemicals in solvent-free aqueous phases.