An improved technique of preparing bone-marrow specimens for cytogenetic analysis

Summary Sixty-six bone-marrow specimens, derived from patients with hematological and non-hematological disorders, were processed for cytogenetic analysis. Modifications of various parameters of the standard (direct) culture procedure were investigated and the quality of the preparations determined. As a result of these experiments, an improved culture technique was developed that yielded significantly better quality chromosome preparations. This method is based on a short incubation (25-min) of the bone-marrow specimen, immediately following aspiration, in a solution containing both hypotonic KCl and colcemid and completely omits the use of tissue culture medium. In partial fulfillment of the requirements for the M.Sc. degree (YS) at the Hebrew University, Jerusalem. Supported by grants from The Ber Lemsdorf Foundation for Cancer Research; The Leukemia Research Foundation; and The US-Israel Binational Science Foundation.     

Protein differences between fruits of rin,a non-ripening tomato mutant,and a normal variety

Summary Fruit extracts of non-ripening tomato Lycopersicon esculentum Mill strain rin contain extra protein band comparing with the normal ripening cultivar Rutgers. Another band exists in both varieties, but disappears in Rutgers at the onset of ripening. The existence of a proteinaceous ripening inhibitor is suggested.     

Nonopioid Effect of Morphine on Electrically Evoked Acetylcholine Release from Torpedo Electromotor Neurons

The release of acetylcholine from Torpedo electric organ slices following their electrical stimulation was modulated by morphine, by the muscarinic antagonist atropine, and by the nicotinic antagonist tubocurarine. Addition of either atropine or tubocurarine in the presence of the acetylcholinesterase inhibitor phospholine iodide enhanced acetylcholine release. The effects of the two antagonists were additive, a result suggesting that the secreted acetylcholine regulates its own release by activating both muscarinic and nicotinic cholinergic receptors and that these receptors inhibit acetylcholine release by different mechanisms. The effects of opiates on acetylcholine release were examined under conditions in which the cholinergic modulation of release is blocked, i.e., in the presence of atropine and tubocurarine. These experiments revealed that electrically evoked release of acetylcholine is blocked by the opiate agonists morphine and levorphanol. However, the inhibitory effect of morphine on acetylcholine release was not reversed by the opioid antagonist naloxone. Furthermore, dextrorphan, the nonopioid stereoisomer of levorphanol, had the same inhibitory effect as its opioid counterpart. These findings suggest that the effects of opiates on electrically evoked release of acetylcholine are not mediated by opioid receptors. The possible mechanisms underlying these nonopioid effects of morphine and levorphanol are discussed.     

Metaxenia in the vine cacti Hylocereus polyrhizus and Selenicereus spp

BACKGROUND AND AIMS: Flowers of the vine cacti of the genera Hylocereus and Selenicereus grown in Israel must be hand pollinated due to self-incompatibility and lack of efficient pollinators. In controlled pollination experiments, it was found that the time elapsed between pollination and ripening depends on the source of the pollen. Therefore a study was made of some effects of the pollen source on fruit development. METHODS: Flowers of Hylocereus polyrhizus were pollinated on the same day with different pollen sources and the stigmas were covered. Fruits were collected 4 d after reaching full colour. RESULTS: Pollinating flowers of Hylocereus polyrhizus with Selenicereus grandiflorus and S. megalanthus pollen delayed ripening by 1 and 3 weeks, respectively, as compared with ripening of fruits pollinated with Hylocereus undatus pollen. Other fruit characteristics affected by the pollen source were fruit size, pulp dry weight and number of seeds per fruit, all being significantly reduced, while peel dry weight was significantly increased by S. megalanthus pollen. Total soluble sugar content was reduced in H. polyrhizus fruits pollinated with S. grandiflorus pollen. No other major traits were affected. CONCLUSIONS: The results are evidence for the existence of metaxenia, i.e. an effect of pollen on maternal tissues, in cacti fruits. This pollen effect on the fruit-ripening time may be used for extending the marketing period of H. polyrhizus fruits.     

Inhibition of tumor growth by poly(ethylene glycol) derivatives of anti-ErbB2 antibodies

Poly(ethylene glycol) (PEG) modification of substances with antitumor activity was shown to enhance penetration into growing solid tumors and extend antitumor effects. Accordingly, PEG was introduced as a modifier to two types of monoclonal antibodies (N12 and L26) specific to the ErbB2 (HER2) oncoprotein. These antibodies suppress the growth of tumors overexpressing ErbB2 (e.g. N87 human tumor) and the effect of PEG on their antitumor activity was evaluated. Methoxy-PEG-maleimide conjugated to sulfhydryl groups at the hinge region of the antibodies impaired their antibody binding to N87 tumor cells and did not enhance the antitumor inhibitory activity in tumor-bearing mice. A branched N-hydroxysuccinimide-activated PEG (PEG2), conjugated through amino groups of the protein, was used for binding to the whole antibody (Ab) or to its monomeric Fab′ fragment. When tested against N87 cells in vitro, the binding activity and antitumor cytotoxic effects of Ab-PEG2 were mostly preserved. PEG2 modification did not seem to alter the tumor-inhibitory activity of the antibodies in vivo and the same pattern of tumor development was observed during the first few weeks following administration. However, the stimulating effects of PEG were observed at later stages of tumor growth since tumor development was either slowed down or completely arrested. Furthermore, a second tumor implanted into the same mice during this later stage was significantly or completely inhibited, as compared to results in mice injected with the unmodified antibody. The Fab′-PEG2 monomeric derivative was also shown to be effective in inhibiting the growth of a second tumor. The extended and prolonged enhancing effect of PEG on the antitumor activity of antibodies or Fab′ fragments directed against ErbB2 may be of importance in the treatment of ErbB2-overexpressing neoplasms. Received: 2 September 1999 / Accepted: 19 February 2000     

Maintaining integrity

Research on genome stability and integrity now extends far beyond the biochemistry of DNA repair to encompass signal transduction pathways that span numerous aspects of cellular life. Derailed genomic integrity pathways can result in debilitating genetic disorders, premature ageing, predisposition to cancer and degenerative conditions. Current progress in this rapidly expanding field was the subject of an EMBO workshop, Maintenance of Genomic Integrity, that took place in June 2004 in Galway, Ireland. Top