Sequencing, expression, and enzymatic characterization of beta-hexosaminidase in rabbit lacrimal gland and primary cultured acinar cells

The lysosomal enzyme, beta-hexosaminidase, exists as two major isoforms; HexA and HexB. HexA is an alpha beta-subunit heterodimer and HexB a beta-subunit homodimer. Both isoforms can remove nonreducing beta-N-acetyl-D-glucosamine residues, whereas HexA hydrolyzes charged substrates as G(M2) gangliosides as well. beta-Hexosaminidase is present in both human and rabbit tear fluid and is secreted from rabbit lacrimal gland acinar cells in primary culture on stimulation with secretagogs. To further characterize the enzyme, the alpha- and beta-subunit mRNA expression was explored in rabbit lacrimal gland tissue as well as in cultured cells. Possible correlation between mRNA expression and HexA specific enzymatic activity was also investigated. Because existing beta-hexosaminidase antibodies are unable to recognize the rabbit enzyme, cloning and sequencing of the alpha- and beta-subunits were performed. Sequencing of the these subunits indicate that both are highly conserved between human, mouse, and rabbit. In contrast to the beta-subunit, showing an even mRNA expression between tissue and cultured cells, the level of alpha-subunit expression was higher in cultured acinar cells compared to tissue, with no alteration after cell stimulation. A minor but significant increase in total beta-hexosaminidase as well as HexA activity was observed in cultured cells compared to tissue. Enzymatic activity assays also revealed that HexA is the dominating isoform of beta-hexosaminidase in lacrimal gland and cultured acinar cells.     

Fertilization and rejection of spermatozoids by egg cells in artificially pollinated ovules ofEncephalartos (Zamiaceae)

The structure and behaviour of free female, male and proembryonal nuclei ofEncephalartos villosus Lem. were studied during a light-microscopical investigation of serially sectioned archegonia in successfully pollinated ovules. Before spermatozoids were released from the pollen tubes into the archegonial chamber, the ventral canal nucleus had disintegrated in the neck region of the egg cell among minute, amoeboid bodies with PAS-positive granules. In archegonia containing multiple spermatozoids, the egg nucleus was unobtrusive and syngamy followed by proembryo formation regularly resulted. The egg cell usually reacted violently in archegonia penetrated by a single spermatozoid. These reactions were regarded as rejection phenomena and considered as indicators that the egg cell can differentiate between compatible and incompatible male gametes.     

Characteristics of Hormogonia Formation by Symbiotic Nostoc spp. in Response to the Presence of Anthoceros punctatus or Its Extracellular Products

Nostocacean cyanobacteria typically produce gliding filaments termed hormogonia at a low frequency as part of their life cycle. We report here that all Nostoc spp. competent in establishing a symbiotic association with the hornwort Anthoceros punctatus formed hormogonial filaments at a high frequency in the presence of A. punctatus. The hormogonia-inducing activity was produced by A. punctatus under nitrogen-limited culture conditions. The hormogonia of the symbiotically competent Nostoc spp. were characterized as motile (gliding) filaments lacking heterocysts and with distinctly smaller cells than those of vegetative filaments; the small cells resulted from a continuation of cell division uncoupled from biomass increase. An essentially complete conversion of vegetative filaments to hormogonia occurred within 12 h of exposure of Nostoc sp. strain 7801 to A. punctatus growth-conditioned medium. Hormogonia formation was accompanied by loss of nitrogen fixation (acetylene reduction) and by decreases in photosynthetic CO₂ fixation and in vivo NH₄⁺ assimilation of 30% and approximately 40%, respectively. The rates of acetylene reduction and CO₂ fixation returned to approximately the control rates within 72 to 96 h after hormogonia induction, as the cultures of Nostoc sp. strain 7801 differentiated heterocysts and reverted to the vegetative growth state. The relationship between hormogonia formation and symbiotic competence is discussed.     

Activated human langerhans cells express mRNA for IL-1α and IL-1β and produce these cytokines but do not secrete them

Human Langerhans cells (LC) were isolated from epidermal cell preparations by panning with mouse anti-CD1 monoclonal antibody. RNA was prepared and probed for the presence of mRNAs for various cytokines using radiolabeled cDNAs. After stimulation with phorbol myristate acetate LC express RNA for interleukin 1α (IL-1α) and interleukin 1β (IL-1β) and produce proteins but do not secrete them at detectable levels. LC-associated IL-1, particularly IL-1α, may play a role in antigen presentation. PMA did not induce IL-6 expression in LC. The addition of lipopolysaccharide, a muramyl dipeptide analog, ionomycin, IL-1α, tumor necrosis factor-α, insulin-like growth factor-1 or IL-6 did not induce IL-1 mRNA in LC. UVB augmented IL-1β mRNA expression. Glucocorticoids did not detectably affect IL-1α or IL-1β mRNA levels following PMA induction, however, staurosporin inhibited IL-1β mRNA synthesis. Thus the inducers and regulators of IL-1 formation in human LC and monocytes are not identical.     

Autophagy induced by a sulphamoylated estrone analogue contributes to its cytotoxic effect on breast cancer cells

Background

The conventional radical resection of proximal gastric cancer is even more risky when performed laparoscopically, though this technique is widely used in gastrointestinal surgery and is accepted as the superior method. This paper explores the feasibility of laparoscopic spleen-preserving hilar lymph node dissection using a retro-pancreatic approach for the treatment of proximal gastric cancer.

Methods

Two cadavers were dissected for examination of and the pre-pancreatic and retro-pancreatic spaces. Following the dissection of the cadavers, ten live patients with proximal gastric cancer from May 2008 to May 2013 at Nanfang Hospital, Guangzhou, China, were given total gastrectomy and adjuvant splenic hilar lymph node clearance through pre-pancreatic and retro-pancreatic approach on the precondition of preserving the pancreas and spleen. The clinicopathologic characteristics, as well as the intraoperative and postoperative variables affecting the procedure, were observed and analyzed.

Results

Anatomy of the space anterior and posterior to the pancreas in the two cadavers demonstrated the feasibility of pre-pancreatic and retro-pancreatic approach. The surgeries were all successfully performed laparoscopically; conversion to laparotomy was not necessary for any of the ten patients. The overall mean operative time was 243.6 ± 45 min. The mean estimated blood loss was 232 ± 80 ml. At the time of follow-up (median 12 months post-surgery), there had been neither local recurrence nor mortality in any of the patients.

Conclusion

Laparoscopic spleen- and pancreas-preserving splenic hilar lymph node dissection during total gastrectomy, using both pre-pancreatic and retro-pancreatic approaches, is indicated as a safe and feasible method for the treatment of proximal gastric cancer.