Sesquiterpene antitumor agents: inhibitors of cellular metabolism

Helenalin and tenulin injected into CF1 male mice bearing Ehrlich ascites tumors inhibit DNA synthesis and DNA polymerase enzymatic activity in the tumor cells. Helenalin inhibited protein synthesis. Both drugs increased the concentration of adenosine 3',5'-monophosphate, and interfered with glycolytic and mitochondrial energy processes. Cholesterol synthesis was also inhibited, resulting in lower serum cholesterol levels in tumor-bearing animals. Data obtained in vitro indicate that the cyclopentenone-bearing sesquiterpene lactone and related compounds do not alkylate puring bases of nucleic acids but rather undergo a Michael-type addition reaction with the sulfhydryl groups of reduced glutathione and l-cysteine. Thus, the inhibition of cellular enzyme activities and metabolism that has been observed with these drugs might be explained by the occurrence of a Michael-type teaction.

Antitumor agents. 21. A proposed mechanism for inhibition of cancer growth by tenulin and helenalin and related cyclopentenones

Evidence is presented that sesquiterpene lactones or ketones containing the O=CC=CH2 moiety, e.g., tenulin and helenalin, alkylate the thiol group of reduced glutathione and L-cysteine in vitro. A proposal is offered that this mechanism of action is responsible for the observed potent in vivo antitumor activity of these agents in the Ehrlich ascites and Walker 256 carcinosarcoma and to a lesser extent in the P388 leukemic screen. Inhibition of tumor growth is thought to occur due to the O=CC=CH2 system alkylating by rapid Michael addition the SH biological nucleophiles of key regulatory enzymes of nucleic acid and chromatin metabolism. This proposition is in accord with the ability of these agents to inhibit DNA synthesis and gene activity of Ehrlich ascites cells.

Myofeedback for muscle retraining in hemiplegic patients

The use of audiovisual displays of myoelectric potentials (myofeedback) has been suggested for retraining and strengthening of paretic muscles in patients with hemiplegia from stroke. This controlled study examines the specificity and efficiency of myofeedback in the strengthening of paretic muscles in hemiplegic patients. Eighteen patients with trace to fair-minus grade of deltoid muscle power resulting from strokes that had occurred at least six weeks earlier were randomly assigned to the six possible orders of accurate (true), positive noncontingent (placebo) and no feedback conditions. On three successive days, each patient received one session of each feedback condition, consisting of 20 isometric contractions of five seconds each with ten seconds of intervening rests. In addition, each patient's motivational level was rated. Averaged myoelectric potentials were quantified for each contraction for analysis. When the data were analyzed without grouping, no statistical differences among the three feedback conditions were noted. However, when the subjects were grouped according to age and motivational level, during true and no feedback sessions, the older and the poorly motivated groups were found to show progressive increment of myoelectric output, whereas the younger and the better motivated showed the opposite results. With placebo feedback, both groups showed progressive decrement of myoelectric output. It is concluded that the effect of myofeedback is nonspecific at least in its short-term application for the retraining of hemiplegically paretic muscles.

The mechanism of increased renal clearance of amylase in acute pancreatitis

Amylase isoenzymes, separated by polyacrylamide gel electrophoresis, were measures in 25 normal persons (mean amylase to creatinine clearance ratio 3.0%), 15 patients with acute pancreatitis (mean clearance ratio 9.5%, P less than 0.0001), and 6 patients with hyperamylasemia due to common duct stones (mean clearance ratio 4.1%). Two isoamylases (P1, P2) resembling pancreatic isoenzymes and three isoamylases (S1, S2, S3) resembling salivary isoenzymes appeared regularly in normal serum and urine. Salivary amylases predominated in serum, but pancreatic amylases predominated in urine. This finding is consistent with renal clearance of pancreatic amylases exceeding that of salivary amylases under normal conditions. In patients with pancreatitis or common duct stones, essentially all of the increased amylase activity in serum and urine was due to pancreatic isoamylases (P1 and P2) in their normal proportions. No new or altered amylase isoenzymes were detected. The fraction of pancreatic amylases in the serum or urine was identical for the two diseases. Whereas the difference in amylase to creatinine clearance ratios observed between the two groups of patients is not a function of different amylase isoenzymes presented to the kidney, we conclude that the increased amylase clearance in acute pancreatitis is caused by an alteration of renal transfer of amylase, either at the glomerulus or tubule.

Genetic regulation of storaage protein content in maize endosperm

Sodium dodecylsulfate-polyacrylamide gel electrophoresis reveals that zein prepared from normal maize inbred (Zea mays L.) contains six separable components. Z1 and Z2 are the predominant species, with molecular weights of 21,800 and 19,000 daltons. Amino acid analysis of these two components shows that both are rich in glutamic acid, leucine, and proline, but low in lysine. Of the four minor bands, Z3, Z4, Z5, and Z6, the latter two exist only in trace amounts. A mutation at the opaque-2 locus severely suppresses the synthesis of Z1. The nonallelic mutant, opaque-7, strongly suppresses the synthesis of Z3 and Z4, while slightly reducing Z2. On the other hand, the floury-2 mutant appears to reduce the synthesis of these six proteins in the same relative proportion. In the double mutant combinations, opaque-2 apparently is epistatic to opaque-7 and floury-2 in the synthesis of zein components. The glutelin fraction shows a more complex banding pattern; however, qualitative differences are not apparent among the mutant lines examined.

Electrically induced flexion reflex in gait training of hemiplegic patients: induction of the reflex

Since the introduction of the concept of functional electrical stimulation, the use of multiple stimulation sites to activate several paretic muscles in a coordinated fashion during ambulation has been suggested. Rather than stimulating multiple muscles, we have applied a train of electrical pulses to a single skin area to activate several muscles simultaneously through the induction of a flexion reflex, and evaluated the effectiveness of this reflex in producing or assisting the swing phase of the gait cycle in the hemiplegic patient. Two considerations in selecting the best stimulus site were (1) the magnitude of the reflex as measured by the length of time the foot was off the floor following a stimulus and (2) the patient's tolerance to the stimulus. The magnitude of the reflex was proportional to the strength of the stimulus current in all skin areas tested; namely the sole, dorsum of the foot, and lower posterior thigh. Of the six patients tested a flexion reflex was not elicitable by sole stimulation in one and by posterior thigh stimulation in another. In every case, compared to the two other areas, stimulation of the sole was best tolerated and produced responses of equal or greater magnitude with the same intensity of current, even though larger voltages were required owing to greater tissue impedances. With a fixed frequency of 30 Hz, a pulse duration of 3 msec, and a stimulus current sufficient to produce the reflex, the duration of the reflex could be adjusted for each patient by varying the train duration from 100 to 700 msec. This technique offers a means of providing or assisting the swing phase in the gait training of the hemiplegic patient.

Grafting of enzymes on collagen films using Woodward's reagent "K" and a water-soluble carbodiimide derivative

Two new methods of activation were developed to graft enzymes on collegen films. They involved chemical modifications of surface groups of collagen either by Woodward's reagent "K" or by EDC, a water-soluble derivative of carbodiimide. EDC was a better coupling agent and a detailed study was conducted with this agent. It could be used either in a global method of activation and coupling, or in a two-step procedure of activation of collagen, followed by spontaneous coupling of enzyme. All enzymes tested were successfully bound: malate dehydrogenase, lactate dehydrogenase, aspartate aminotransferase, urease, creatine kinase, hexokinase. The influence on the yield of grafted enzyme, of pretreatment of films, time and temperature of EDC activation, concentration of EDC and enzyme, protecting agents was studied. Stability of enzyme activity on storage was greatly increased after grafting. A co-grafted dual system creatine kinase/heoxkinase, was achieved which exhibited a good efficiency. A striking renaturing process at 0-4degreesC after thermal denaturation, was observed with hexokinase.

Analysis of dose, dose-rate and treatment time in the production of injuries by radium treatment for cancer of the uterine cervix

A retrospective study has been made of 15 patients who had developed severe complications to the bladder, rectum and ureters after radiation therapy for carcinoma of the cervix. Comprehensive dose distribution in the pelvis were calculated with computer assistance to visualize how the normal organs had been irradiated. The risk of normal tissue injury was analysed graphically with respect to the maximum radium dose, dose-rate and irradiation time. The two groups of data representing the injured and non-injured organs separate much better in a dose-rate versus dose plot than in a conventional Strandqvist type dose-time plot. This implies that in radium therapy, the dose-rate rather than the treatment time, is the important parameter in modifying the risk of normal tissue injury. Our results show a good separation of injured from non-injured cases only when the maximum values of dose and dose-rate were used. This suggests that clinically significant injury may develop from relatively small regions of high dose and dose-rate. Since the dose-rate varies from point to point in the pelvis (unlike treatment time), comprehensive determinations of dose-rate distributions are required in order to locate the sites of potential injuries.

Mechanism of action of retinyl compounds on wound healing IV: effect of desmethylretinoic acid and its vinylogs on granuloma formation

The effect of side-chain length of desmethylretinoic acid on granuloma formation induced by implantation of cotton pellets was studied. As in the homologous series of retinoic acid studies, compounds with side chains shorter than retinoic acid were not active while compounds with side chains as long or longer than retinoic acid were active. The compound with a chain two carbons longer than retinoic acid was the most active. The hydroxyproline and hexosamine contents of the granuloma were analyzed. The mechanisms of action of these active compounds on wound healing are discussed.

Electrophoretic identification of an isoenzyme of amylase which increases in serum in liver diseases

Isoenzymes of amylase were studied in serum from 72 persons by means of polyacrylamide gel electrophoresis and a direct saccharogenic assay for amylase activity. In 37 normal individuals, there were two major peaks of amylase actvity with mobilities similar to pancreatic and salivary amylases. In 11 patiets with acute pancreatitis, the area of activity corresponding with pancreatic amylases increased disproportionately. Electrophoretic patterns of amylase activity in normal and pancreatitis urine were almost identical to the respective serum patterns from the same persons. In contrast, a prominent slower-moving peak of amylase activity occurred in the serum of 8 of 12 patients who had hyperamylasemia associated with various liver diseases. Traces of this third peak were identifiable in one-third of normal serum specimens, but no increases in its activity were observed in any specimen from 11 patients with pancreatitis or from 12 other patients with hyperamylasemia unassociated with liver disease. The slower-moving peak was absent from the urine of patients whose serum contained it. The origin of the slower-moving serum amylase appearing in patients with liver disease is not established by these studies. It is possible either that a hepatic amylase is liberated from damaged liver cells or that the metabolism of an amylase not originating in the liver is altered as a result of liver dysfunction.

Antitumor agents. XV: Deoxyelephantopin, an antitumor principle from Elephantopus carolinianus Willd

The active principle responsible for the significant inhibitory activity against the Walker 256 carcinosarcoma (ascites) in rats, isolated from the chloroform extract of the whole plant of Elephantopus carolinianus Willd., was characterized as deoxyelephantopin, a sesquiterpene lactone.

Antitumor agents. 16. Steroidal alpha-methylene-gamma-lactones

Several novel steroidal alpha-methylene-gamma-lactones and related derivatives have been synthesized as potential steroid alkylating antitumor agents. The synthesis of these compounds involved the convenient Reformatsky-type reaction between ethyl-alpha-(bromomethyl)acrylate and the proper steroidal ketones. In vitro assay for the cytotoxicity of these compounds against the growth of tissue culture cells originating from human epidermoid carcinoma of the larynx (H.Ep.-2) has shown significant activity. Cytotoxicity was improved at least sixfold with the introduction of lipophilic steroidal character. Preliminary in vivo tumor assay also indicated that these compounds were active against Walker 256 carcinosarcoma in rats and were inactive against both L1210 lymphoid leukemia and Ehrlich ascites carcinoma in mice. However, the simple alpha-methylene-beta,beta-dicarbethoxy-gamma-butyrolactone significantly inhibited Ehrlich ascites tumor growth.

Effect of uridine diphospho-N-acetylglucosamine and sodium salicylate on L-glutamine-D-fructose-6-phosphate aminotransferase activity from rat gastric mucosa

Mechanisms of inhibitory action of sodium salicylate on L-glutamine-D-fructose-6-phosphate aminotransferase, prepared from rat gastric mucosa, were studied. Sodium salicylate at lower concentrations (10-20 mM) inhibited reversibly aminotransferase activity by competing with fructose-6-phosphate. At higher concentrations, sodium salicylate inactivated the enzyme irreversibly, with an inactivation rate following first-order kinetics with respect to the enzyme concentration. Uridine-5'-diphospho-N-acetylglucosamine is an endogenous feedback inhibitor. It inhibited the aminotransferase-catalyzed reaction also by competing with fructose-6-phosphate but with an inhibiting activity 1000 times that of sodium salicylate. Uridine-5'-diphospho-N-acetylglucosamine reduced the salicylate inhibition of the enzymic reaction and protected the enzyme from salicylate-induced irreversible inactivation. At a fixed concentration of uridine-5'-diphospho-N-acetylglucosamine (7x10(-6)M), an increase of salicylate concentration produced an increase in enzyme activity as compared with the control.

Comparison of analgesic effects of isosteric variations of salicylic acid and aspirin (acetylasalicylic acid)

A reliable and sensitive method was used to compare the analgesic activities of salicylic acid and aspirin (acetylsalicylic acid) and several phenoxy substituted isosteric pairs. Those isosteric compounds studied did not show analgesic activity. The analgesic activity of aspirin was more than twofold greater than that of salicylic acid.

Antitumor agents. 11. Synthesis and cytotoxic activity of epoxides of helenalin related derivatives

Several epoxides of helenalin related derivatives have been synthesized in an effort to evaluate the potential significance of the epoxycyclopentanone moiety for cytotoxic activity against the growth of tissue culture cells originating from human epidermoid carcinoma of larynx (H.Ep-2). Helenalin (1) was converted to the monoepoxy derivative 2 and the diepoxy derivative 3 by alkaline hydrogen peroxide at different temperatures. Alternative synthesis of 2 was achieved by a convenient method of protecting the alpha-methylene grouping of the gamma-lactone, i.e., epoxidation of helenalin dimethylamine adduct 4, followed by treatment of the reaction product 5 with m-chloroperbenzoic acid. 2,3-Epoxy-11,13-dihydrohelenalin (8) was prepared by direct epoxidation of 11,13-dihydrohelenalin (7). Treatment of mexicanin A (9) with m-chloroperbenzoic acid gave, in addition to the 1,2-epoxy derivative 10, 1-alpha-hydroxyhelenalin (11) which furnished an acetate (12) upon acetylation. Catalytic hydrogenation of 10 yielded the dihydroepoxide 13. Treatment of 1 or acetylhelenalin (15) with Ac2O-p-TsOH gave the same acetyl dienol acetate (14). Epoxidation of 14 with m-chloroperbenzoic acid gave 1,beta hydroxyhelenalin (19) and a mixture of monoepoxides (17 and 18) which yielded 19 and 11 upon silica gel chromatography. The results of the cytotoxicity test of the compounds studied indicate that either an alpha- or a beta-epoxycyclopentanone moiety in helenalin related derivatives contributes significantly to the cytotoxicity. Furthermore, this cytotoxicity appears to be independent of the presence or absence of an alpha-epoxy-gamma-lactonic moiety.

Effects of n-alkanes on Cladosporium resinae

Growth of three different soil isolates of Cladosporium resinae on a large number of carbon compounds was found to be inhibited by n-hexane and n-heptane whereas n-octane and all higher liquid n-alkanes had no effect on growth. In addition, n-hexane and, to a lesser extent, n-heptane caused rapid inhibition of glucose incorporation and considerable loss of potassium and protein from the cells. The phenomenon is unlikely to be due to removal of membrane lipids such as sterols and phospholipids by the n-alkanes, but rather to a limited disorganization of the cell membrane resulting in rapid loss of selective permeability.

Utilization of n-alkanes by Cladosporium resinae

Four different isolates of Cladosporium resinae from Australian soils were tested for their ability to utilize liquid n-alkanes ranging from n-hexane to n-octadecane under standard conditions. The isolates were unable to make use of n-hexane, n-heptane, and n-octane for growth. In fact, these hydrocarbons, particularly n-hexane, exerted an inhibitory effect on spore germination and mycelial growth. All higher n-alkanes from n-nonane to n-octadecane were assimilated by the fungus, although only limited growth occurred on n-nonane and n-decane. The long chain n-alkanes (C(14) to C(18)) supported good growth of all isolates, but there was no obvious correlation between cell yields and chain lengths of these n-alkanes. Variation in growth responses to individual n-alkane among the different isolates was also observed. The cause of this variation is unknown.

Correlation between the foetal acid-base status and the Apgar score

The foetal pH values of eighty-eight cases delivered within 30 min after foetal blood sampling were correlated with the 1-min Apgar score. With a pH of 7·20 or above the error of prediction was 1·3%. The error in cases with pH below 7·20 was 54·5%.

Significantly higher pH and lower δ base deficit were present in the low foetal pH group in vigorous, as opposed to depressed infants, suggesting that infusion acidosis was present in infants with a high Apgar score.

The degree of correlation between the foetal pH and the Apgar score was not significantly influenced by shortening the sampling-delivery interval to 15 min or lengthening it to 3 hr. The most significant factor affecting the degree of correlation in the present study was the setting of the critical pH. If the criterion of the critical pH was taken as 7·13 there would have been no false positive results and the error of prediction in cases delivered within 30 min of foetal blood sampling would be reduced to 1·1%.

Foetal acid-base status in clinical foetal distress and high risk cases

The acid-base balance in 307 Chinese patients in labour was studied in Tsan Yuk Hospital, Hong Kong over a 15-month period. Fifty-six of these were normal cases, 200 cases exhibited clinical signs of foetal distress and the other fifty-one were high risk cases. The results showed that cases of clinical foetal distress had a significantly lower foetal pH than that in the normal control group. Of the different signs of clinical foetal distress, meconium was the least important and foetal tachycardia appeared to be more significant than the others. Cases of postmaturity and uterine inertia also gave a lower foetal pH than normal. It is concluded that foetal blood sampling is indicated in these types of cases.