Structure-function relationships of alkyl-lysophospholipid analogs in selective antitumor activity

This investigation was initiated in order to delineate the structure-function relationship of the anticancer alkyl-lysophospholipids and assess their degree of selective cytotoxicity toward neoplastic cells. A series of glycerol phosphocholine analogs with varying substitutions in the sn-1 and sn-2 position were tested for their inhibitory activity as measured by thymidine incorporation, clonogenic assays and effects on protein kinase C activity against a series of human leukemic cell lines and healthy bone marrow progenitor cells. The IC50 was determined for each of the compounds in each cell line and healthy bone marrow cells following a 4-h incubation. The data indicated that a 16-18 carbon chain at the sn-1 coupled with a short substitution at sn-2 had the broadest antitumor activity and was the least toxic to normal bone marrow cells. The results provide a number of useful leads toward the design and development of potentially more active phospholipid compounds.

Use of the polymerase chain reaction to detect hypermethylation in the calcitonin gene. A new, sensitive approach to monitor tumor cells in acute myelogenous leukemia

Based on the recent observations that, in a majority of patients with acute leukemia, the 5' end of the calcitonin gene was hypermethylated and abnormal DNA fragments were observed following HpaII restriction digestion, we have developed a PCR-based method to sensitively detect this abnormal methylation of the calcitonin gene in AML. Applying the concept of competitive PCR, a semi-quantitative correlation was obtained between the amount of hypermethylation and the amount of leukemic cells present. These results suggest that this method will be useful to monitor the amount of tumor cells in bone marrow from patients with AML.

Autologous bone marrow transplantation in acute leukemia with marrow purged with alkyl-lysophospholipid

Alkyl-lysophospholipids are anticancer agents that are selectively toxic to leukemic cells and relatively sparing of normal bone marrow cells. Thus, they would be likely candidates for purging remission marrows before autologous bone marrow transplant. One of the more promising agents is edelfosine, which could be safely used for purging without prolonging marrow recovery. Assays for marrow progenitor cells were performed before and after purging and cryopreservation in 64 patients. There was no significant reduction in colony formation after purging when compared with unpurged cryopreserved marrow, but there was a significant reduction after cryopreservation. Twenty-four patients with acute leukemia in second (16 patients) or third remission (3 patients), early relapse (3 patients), or in first remission with successfully treated extramedullary relapse (2 patients) received marrow-ablative chemotherapy and total body irradiation followed by infusion of marrow purged for 4 hours with 50 to 100 micrograms/mL of edelfosine. There were 9 lymphoblastic and 15 myelogenous leukemia patients. The median time to granulocyte recovery to 500/microL was 26 and 33 days for the 50 and 75 microgram/mL doses, respectively. The patient whose marrow was purged at the dose of 100 micrograms/mL failed to engraft. The median time to platelet recovery to 25,000/microL was 45 and 37 days for the 50 and 75 micrograms/mL doses, respectively. Twenty-nine percent of the patients remain disease free from 131 to 1,291 days, with a median of 356 days. These results have established that purging with 75 micrograms/mL of edelfosine is a safe dose and is recommended for a phase II trial.

Comparison of selective cytotoxicity of alkyl lysophospholipids

Alkyl lysophospholipids have been shown to be cytooxic to a number of neoplastic tissues. One, ET-18-OCH3, has been used to selectively purge leukemic cells from mixtures with normal marrow progenitor cells, in vitro and in vivo. We have measured the 50% inhibitory (IC50) effect of a series of ether lipids (EL) on leukemic cells (HL60, K562, Daudi, KG-1, KG-1a) and normal marrow progenitor cells. Cells were incubated with varying concentrations of EL for 4 hr and assayed for viability, [3H]thymidine incorporation and clonogenicity in semi-solid media. The effect on protein kinase C (PKC) activity was assayed for each compound. Compounds tested included three glycerophosphocholine analogs--ET-18-OCH3, ET-16-NHCOCH3, and BM 41.440. In addition, a lipoidal amine, CP 46665, an ethyleneglycolphospholipid, AEPL, and four single chain alkylphosphocholine analogs, HePC2, HePC3, HePC4 and HePC6 were also tested. During the period of incubation, the cells remained viable (greater than 70%) as judged by trypan blue dye exclusion. The glycerophosphocholines were the most active and showed the highest therapeutic index. The lipoidal amine was active, but toxic to normal marrow progenitor cells. The ethyleneglycolphospholipid was active against HL60, but not against the other cell lines. The single chain alkylphosphocholine analogs were less active. All of the compounds inhibited PKC activity; however, the glycerophosphocholines were the most inhibitory.

Purging of acute myeloid leukemic cells by ether lipids and hyperthermia

Ether lipids (EL) and hyperthermia have been shown to possess a relatively selective cytotoxicity to leukemic cells. In this study, the combined effects of EL (ET-18-OCH3, ET-16-NHCOCH3, or BM 41.440) and hyperthermia on the growth of hematopoietic progenitors, myeloid leukemic cell lines, and leukemic cells obtained from patients with acute myeloid leukemia (AML) were examined to determine if this combination resulted in a greater selective killing of leukemic cells than that achieved by either EL or heat alone. When the cells were treated simultaneously with EL (50 micrograms/mL) and hyperthermia (42 degrees C) for one hour, the killing of leukemic cell line cells was enhanced considerably. Among the three EL, however, the combination of ET-18-OCH3 and heat seemed to be the most cytotoxic to leukemic cell line cells with no effect on the growth of hematopoietic progenitors. An increase in the duration of treatment with ET-18-OCH3 to four hours with heat added during the last hour resulted in a further reduction of leukemic cell line cells while sparing 50% of hematopoietic progenitors after cryopreservation. The combined treatment with ET-18-OCH3 and heat also inhibited the growth of leukemic progenitors obtained from AML patients by 97% to 100%. These data indicate that the combined treatment with EL and hyperthermia might offer an efficient means to eliminate myeloid leukemic cells in vitro.

Experimental studies on the role of alkyl lysophospholipids in autologous bone marrow transplantation

The selective cytocidal effect of alkyl lysophospholipids against neoplastic cells while sparing normal cells make these ideal candidates for purging leukemic cells from bone marrows obtained during remission. To test the feasibility of such an approach, a murine model and an in vitro human cell model were developed. In the murine system a mixture of normal bone marrow cells and WEHI IIIB myelomonocytic leukemic cells was incubated with varying doses of 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-Me) for 24 hr before being injected into tail veins of lethally irradiated Balb/c mice. At doses of 20 and 100 micrograms/ml, long-term survivors were noted. The additional steps of freezing and thawing following incubation resulted in significantly longer survival with doses of 10 to 50 micrograms/ml, but were toxic to marrow stem cells at 100 micrograms/ml. In the in vitro model, normal marrow progenitor cells and leukemic cells (the promyelocytic cell line HL60) were exposed to varying concentrations of ET-Me for 1 and 4 hr alone or mixed, and clonogenicity was assayed by colony formation in semisolid medium during 7-14 days' incubation. At doses up to 100 micrograms/ml exposed for 4 hr normal progenitor cells were spared and HL60 colonies eliminated. Other phospholipids analogues were less effective in eliminating leukemic cells, but spared normal progenitor cells. A survey of fresh leukemic cells found varying degrees of sensitivity to ET-Me, indicating the need for testing a variety of compounds. These studies clearly indicated the potential usefulness of alkyl lysophospholipid compounds in selectively purging leukemic cells from remission marrows for autologous bone marrow transplantation.

Elimination of leukemic cells by the combined use of ether lipids in vitro

Two ether lipids, CP-46,665-1 (4-aminomethyl-1-[2,3-(di-n-decyloxy)-n- propyl]-4-phenylpiperidine) and ET-18-OCH3 (racemic 1-O-octadecyl-2-O-methylglycero-3-phosphocholine) have been shown to possess antileukemic activity in vitro. To explore the possible use of these compounds for purging remission bone marrow cells of leukemic cells, we examined the cytotoxic effect of these compounds on normal hematopoietic progenitor cells and leukemic cell line cells (HL-60, K-562, KG-1a, KG-1, and Daudi) by using the clonogenic assay. When cells were treated with CP-46,665-1 or ET-18-OCH3 (50 micrograms/ml for 1 h), these compounds did not inhibit the growth of normal progenitors, whereas the growth of the clonogenic leukemic cells was inhibited with differences in their sensitivities to the cytotoxic effect of CP-46,665-1 and ET-18-OCH3. Incubation of leukemic cells (HL-60 and Daudi cells) with both CP-46,665-1 (50 micrograms/ml) and ET-18-OCH3 (50 micrograms/ml) for 1 h resulted in a greater reduction of clonogenic leukemic cells than treated with each compound alone. Approximately a 3 log killing of clonogenic HL-60 cells and a 5 log killing of Daudi cells was achieved; however, the combined treatment of normal bone marrow cells with CP-46,665-1 and ET-18-OCH3 did not alter the growth of normal progenitors. This combined treatment also selectively eliminated the leukemic cells (HL-60 and Daudi cells) from a mixture (1000:1) of normal bone marrow cells and leukemic cells. It is conceivable that the pronounced difference in sensitivity to this combined treatment can be exploited for the elimination of residual leukemic cells in autologous remission marrow grafts.

Purging leukemic cells from simulated human remission marrow with alkyl-lysophospholipid

Alkyl-lysophospholipids (ALP) are analogues of 2-lysophosphatidylcholine that have been reported to have selective antitumor activity. These compounds could potentially be useful in purging bone marrow of leukemic cells in autologous marrow transplantation in acute leukemia. To determine the efficacy of pharmacological purging by ALP, we have designed a human assay system to mimic the conditions expected in the clinical setting of autotransplantation using remission marrow. A simulated remission marrow (SRM) was prepared by mixing normal marrow cells and HL60 cells in a ratio of 1,000:1. The effect of cryopreservation on ALP-treated normal, HL60, and SRM cells was examined. In separate experiments, ALP significantly reduced the number of clonogenic HL60 cells with no effect on normal marrow progenitors. The effect of ALP was more apparent after cryopreservation. Incubation of HL60 cells with 50 micrograms/mL ALP for four hours followed by cryopreservation resulted approximately in a 3 log reduction of clonogenic HL60 cells. ALP also selectively purged the small number of leukemic cells from SRM. In SRM, the data suggested that ALP had indirect cytotoxic activity on leukemic cells by enhancing the cytotoxic activity of monocytes in addition to its direct effect. We found no evidence that clonogenic HL60 cells decreased because of induction of differentiation by ALP. These data indicated that treatment of marrow cells with ALP offers an efficient means to eliminate leukemic cells from the graft.

Effect of alkyl-lysophospholipids on phosphatidylcholine biosynthesis in leukemic cell lines

Alkyl-lysophospholipids are ether analogues of lysophospholipids that have tumoricidal activity mediated through activation of macrophages or by direct effect on tumor cells by disturbance of phospholipid metabolism. The effect of racemic 1-octadecyl-2-methyl-sn-glycero-3 phosphocholine on phosphatidylcholine synthesis was investigated in sensitive (HL-60) and resistant (K-562) human leukemic cell lines. Radiolabeled lysophosphatidyl-choline, choline, and methionine incorporation into phosphatidylcholine was measured in intact cells exposed for 24 h to varying concentrations of the compound. In HL-60 cells, marked inhibition of phosphatidylcholine synthesis was demonstrated using lysophosphatidylcholine or choline as precursors, but no effect was observed on methionine incorporation. No effects were observed in K-562 cells. These investigations suggest that alkyl-lysophospholipids inhibit phosphatidylcholine synthesis via the acyltransferase reaction and from choline, but not from methionine.

Proper identification of anisakine worms

Luminal, gastric, intestinal and mesenteric forms of anisakiasis are known and can be encountered where raw or undercooked marine fish or squid are eaten. Although the anisakine nematodes which cause infection in humans are usually identified after surgical removal, laboratory personnel should be aware of their similarities to other nematodes. Cases have been reported of detection of larval nematodes in the throats or mouths of patients who have vomited or coughed. When such specimens are submitted to the clinical laboratory, problems in identification can be minimized by proper fixation and clearing. Systems for study involving clearing in phenol-ethanol and dissection to observe presence or absence of a ventricular appendix or intestinal cecum to distinguish Anisakis-, Phocanema- and Contracaecum-type larvae are described. Distinguishing characteristics are illustrated. The recovery of a Phocanema-type larva from a California woman is reported; the presence of the larvae in fish sold for human consumption in San Diego is exemplified.

Role of pH in production of hydrogen from carbohydrates by colonic bacterial flora. Studies in vivo and in vitro

Hydrogen produced by colonic bacteria and excreted in breath is a useful index of carbohydrate malabsorption. Since colonic contents are often acidic in individuals with carbohydrate malabsorption and in normal newborns, we determined the effect of colonic acidification on H2 production. Acidification of colonic contents by dietary means significantly reduced excess breath H2 excretion from 55.4 +/- 11.1 (SEM) to 12.2 +/- 3.1 ml/4 h (P less than 0.05) after administration of 0.3 g/kg of the nonabsorbable sugar lactulose to five normal adult subjects. Similarly, the breath H2 response to lactose was reduced or eliminated in two proven lactose malabsorbers after acidification. The correlation between pH and H2 production from carbohydrate was further investigated in adults and neonates, using an in vitro fecal incubation system. Glucose disappearance and H2 production were pH dependent and highly correlated (r = 0.94) in the pH range 5.5-7.6. Maximal production of H2 from glucose by fecal incubates occurred at pH 7.0-7.45. Inhibition of H2 production from carbohydrate occurred at acid pH. H2 per hour from glucose at pH 6.2 and 5.5 averaged 60.2% and 24.2%, respectively, of that produced at neutral pH. Rapid reversal of pH-induced inhibition by neutralization indicated a metabolic, rather than a bactericidal process. The observations indicate that the breath H2 response to malabsorbed carbohydrate is affected by colonic pH. It appears that the efficiency of bacterial carbohydrate metabolism in the colon is pH dependent.

Classification of cultured mammalian cells by shape analysis and pattern recognition

We have developed a method for classifying cultured cells on the basis of shape characteristics. High-resolution optical information on three-dimensional shape was obtained by anodic oxide interferometry. Each interference order formed in a cell was considered as a closed figure; measurement of 37 mathematical descriptors was carried out for each figure. The individual cells were classified according to the values of their descriptors. We used standard principles of pattern recognition, such as hierarchical cluster analysis and nearest neighbor analysis, as a basis for ordering the cells into groups. Alternatively, linear discriminant functions could be used, but they provided only a slight improvement in correct classification of the cells. We anticipate that the method will be appropriate for classification of cultured cell lines and for determination of the magnitude and direction of cell shape changes implicated in various biological processes.

Electron microscopic studies of bacteriophage M13 DNA replication

Intracellular forms of M13 phage DNA isolated after infection of Escherichia coli with wild-type phage have been studied by electron microscopy and ultracentrifugation. The data indicate the involvement of rolling-circle intermediates in single-stranded DNA synthesis. In addition to single-stranded circular DNA, we observed covalently closed and nicked replicative-form (RF) DNAs, dimer RF DNAs, concatenated RF DNAs, RF DNAs with single-stranded tails (theta, rolling circles), and, occasionally, RF DNAs with theta structures. The tails in theta molecules are always single stranded and are never longer than the DNA from mature phage; the proportion of theta to other RF molecules does not change significantly with time after infection. The origin of single-stranded DNA synthesis has been mapped by electron microscopy at a unique location on RF DNA by use of partial denaturation mapping and restriction endonuclease digestion. This location is between gene IV and gene II, and synthesis proceeds in a counterclockwise direction on the conventional genetic map.

Asymphylodora atherinopsidis (Trematoda: Monorchiidae) from the California grunion, Leuresthes tenuis, including a redescription

Asymphylodora (Asymphylodoroides) atherinopsidis from the California grunion, Leuresthes tenuis, a new host record, and jacksmelt, Atherinopsis californiensis, the type host, is redescribed and illustrated using more symmetrical as well as larger and smaller specimens than the holotype. The geographic distribution is extended from the type locality of Stinson Beach, Marin Co., California to Estero Beach, 10 km south of Ensenada, Baja California Norte, Mexico. Two tubular externat seminal vesicles opening independently into the internal seminal vesicle are reported apparently for the first time in a trematode. The genital pore is at the left posterolateral margin of the acetabulum which is midway between the lateral margins. Worms may grow to a length of 5.6 mm but eggs were present in one specimen 1.3 mm long.

The use of alpha-galactosidase and invertase in hollow fiber reactors

Invertase and alpha-galactosidase have been immobilized in hollow fiber cartridges with no detectable enzyme leakage and used for the hydrolysis of sucrose and raffinose, respectively. For both hollow fiber immobilized enzymes nearly complete substrate conversion is possible. Enzyme stabilities in polysulfonate hollow fibers which have been preconditioned with bovine albumin approach the stabilities of the free enzymes.

DNA replication in Chinese hamster ovary cells made permeable to nucleotides by tween-80 treatment

We have developed a method for permeabilizing CHO cells to nucleotides under conditions which allow most cells to remain viable. Permeabilized cells can carry out ATP-dependent, semiconservative synthesis of DNA. The data are consistent with the continuation of DNA synthesis in those cells in S phase at the time of treatment, possibly limited to completion of replicon synthesis without new initiations.

Hydrogen production in the rat following ingestion of raffinose, stachyose and oligosaccharide-free bean residue

Raffinose and stachyose were compared to cooked California Small White beans (CSW) containing 4% alpha-oligosaccharides (stachyose and raffinose) and to oligosaccharide-free CSW solids (residue from hexane and 70% ethanol extraction of CSW) as sources of hydrogen when ingested by rats maintained in life support systems. If the oligosaccharide content were the only hydrogen source in CSW, it would have had to be 25 times as potent as CSW, but raffinose was only five times and stachyose seven times as potent as CSW. Oligosaccharide-free residue was 0.4 to 0.5 as active as CSW. Hydrogen producing potencies of stachyose and raffinose were enhanced by feeding in combinations with residue. The increases in hydrogen production from the combinations were more than additive. Thus, CSW contains at least one 70% alcohol-insoluble substance which, in addition to the oligosaccharides, is essential to bring about quantitatively the physiological response to whole beans observed in rats.