An Analysis of Dasatinib Treatment Patterns in Patients with Chronic Myeloid Leukemia after Experiencing Pleural Effusion during Dasatinib Therapy

INTRODUCTION

Treatment with dasatinib for chronic myeloid leukemia (CML) has been associated with development of pleural effusion; however, data regarding its optimal management are limited. We examined treatment patterns and healthcare resource utilization (HCRU) and costs among patients with CML treated with dasatinib who experienced a subsequent pleural effusion.

METHODS

Adults with CML and ≥1 pharmacy claim for dasatinib in 2015-2018 who experienced pleural effusion after dasatinib were identified using data from claims databases.

RESULTS

Overall, 123 patients were eligible. After 1 year, of the 38.2% of patients with a dose modification, 72.3% did not switch treatment; among these patients, 70.6% continued treatment. Among patients with a stable dose after pleural effusion (61.8%), 57.9% later switched to another TKI. The mean (SD) duration of dasatinib treatment after pleural effusion was 262.0 (124.0) days for patients with a dose modification versus 149.1 (155.2) days for those with a stable dose (p < 0.001). HCRU and costs were similar between groups.

CONCLUSION

Dasatinib dose modification after pleural effusion was not always required; however, patients with dose modifications continued therapy for a longer duration with a lower rate of switching to another TKI versus patients who remained on a stable dose.

Nanostructuring with Structural-Compositional Dual Heterogeneities Enhances Strength-Ductility Synergy in Eutectic High Entropy Alloy

A lamellar (L1₂ + B2) AlCoCrFeNi_2.1 eutectic high entropy alloy (EHEA) was severely deformed by a novel hybrid-rolling process. During hybrid-rolling, the deformation was carried out in two stages, namely cryo-rolling followed by warm-rolling at 600 °C. The strain (ε) imparted in each of these steps was identical ~1.2, resulting in a total strain of ε~2.4 (corresponding to 90% reduction in thickness). The novel processing strategy resulted in an extremely heterogeneous microstructure consisting of retained lamellar and transformed nanocrystalline regions. Each of these regions consisted of different phases having different crystal structures and chemical compositions. The novel structure-composition dual heterogeneous microstructure originated from the stored energy of the cryo-rolling which accelerated transformations during subsequent low temperature warm-rolling. The dual heterogeneous microstructure yielded an unprecedented combination of strength (~2000 MPa) and ductility (~8%). The present study for the first time demonstrated that dual structure-composition heterogeneities can be a novel microstructural design strategy for achieving outstanding strength-ductility combination in multiphase high entropy alloys.

Improved outcomes for inborn babies with uncomplicated gastroschisis

INTRODUCTION

Gastroschisis (GS) is a common abdominal wall defect necessitating neonatal surgery and intensive care. We hypothesized that inborn patients had improved outcomes compared to patients born at an outside hospital (outborn) and transferred for definitive treatment.

METHODS

A single center, retrospective chart review at a pediatric tertiary care center was performed from 2010 to 2015. All patients whose primary surgical treatment of GS was performed at this center were included. We compared patients delivered within our center (inborn) to patients delivered outside of our center and transferred for surgical care (outborn). Babies with complicated gastroschisis were excluded.

RESULTS

During the study period 79 patients with GS were identified. Of these, 53 were inborn and 26 were outborn. Sixteen patients were excluded for complicated GS. The rate of complicated GS was higher in the outborn group (32%) compared to the inborn population (11%) (p=0.03). Duration of stay, readmission rate and time on TPN were all significantly decreased for inborn patients, while time to definitive closure was similar. Mortality was 0% for both inborn and outborn patients.

CONCLUSION

Patients with uncomplicated GS seem to benefit from delivery with immediate pediatric surgical care available eliminating the need for transfer.

LEVEL OF EVIDENCE

III.

Compensatory changes in enzymes of arginine metabolism during renal hypertrophy in mice

The present study investigates enzyme activities of the urea cycle, transamidinase and ornithine-proline inter-conversion in the hypertrophied kidney after unilateral nephrectomy in mice. Surgical removal of the left kidney in mice led to compensatory enlargement of the right kidney after 1 and 14 days. This renal growth was associated with an increase in glomerular volume (but not number) and enlargement of the proximal convoluted tubules. The total renal protein content increased in proportion to the increase in kidney weight, but the protein per gram weight of kidney did not change. The specific activity of only ornithine aminotransferase (OAT), the rate-limiting enzyme in the conversion of ornithine to proline, increased in 2 weeks of hypertrophy. The specific activity of all other enzymes was unchanged. However, the total enzyme activity per kidney of all the enzymes, without exception, was elevated in the hypertrophied kidney. While the increase in total OAT activity was much more than the increase in kidney weight, all other enzymes increased more or less in proportion to the increase in renal mass. The results suggest that compensation in OAT activity to chronic reduction in renal mass was complete, but only partial in the case of other enzymes.

Medialisation laryngoplasty: a new surgical frontier in the management of vocal cord paralysis

Patients who are victims of vocal cord paralysis usually suffer from husky or hoarse voice which is very much jeopardising their future particularly in professional voice users like singers, priests, teachers, etc. Phonosurgical techniques like medialisation laryngoplasty has opened a new horizon in the management of dysphonia with unilateral vocal cord paralysis. Medialisation laryngoplasty is sometimes described under the heading of laryngoplastic phonosurgery or thyroplasty. A report of 10 cases of unilateral vocal cord paralysis with dysphonia subjected to medialisation laryngoplasty from March 1996 to March 1998 with 90% success is presented. Only one patient developed inspiratory stridor as a complication.

Medialization laryngoplasty with silastic implant in unilateral vocal cord paralysis

The state of art of Laryngoplastic surgery gaining day to day importance where Rhinoplasty stood almost a century ago. Medialization Laryngoplasty using Silastic Implant for the correction of symptomatic unilateral vocal cord paralysis is discussed.

Attenuation of experimental hypertension by dietary linoleic acid is model dependent

OBJECTIVE

The purpose of this study was to evaluate the interaction of a linoleic acid enriched diet with NaCl on the development of hypertension in Dahl salt sensitive (Dahl-S) rats and in two-kidney, one-clip Sprague Dawley rats.

METHODS

In both experimental models, separate groups of animals were fed either linoleic acid enriched (provided as safflower oil) or control (containing coconut oil) diets for 5 weeks. Diets were further subdivided on the basis of either a low NaCl (0.3%) or a high NaCl (3.0%) content. Tail systolic blood pressure, direct mean intra-arterial pressure, and cardiac output were measured in chronically instrumented, conscious rats.

RESULTS

In Dahl-S, on both NaCl intakes, and in two-kidney, one-clip rats on a high NaCl diet, safflower oil had no effect on arterial pressure. In contrast, in two-kidney, one-clip rats fed the low NaCl diet, both indirect tail systolic blood pressures and direct mean arterial pressure were lower (p<0.01) in animals on the linoleic acid enriched diet; total peripheral resistance was also decreased (p<0.01).

CONCLUSION

Safflower oil has a hypotensive effect only in the two-kidney, one-clip rat on a low NaCl, but not on a high NaCl intake, and not in Dahl-S rats. Additional studies are required to identify the mechanism(s) for the hypotensive effect of safflower oil and to define the relationship of this animal study to human hypertension.

Antihypertensive effect of pioglitazone is not invariably associated with increased insulin sensitivity

Hypertension is often associated with insulin resistance, and several chemically diverse agents that increase insulin sensitivity attenuate the development of experimental hypertension. We undertook the present study to determine whether attenuation of hypertension by pioglitazone, a thiazolidinedione derivative that increases insulin sensitivity without increasing insulin secretion, is specifically related to its effect on insulin-mediated glucose uptake. Pioglitazone administered daily by oral gavage (20 mg/kg per day) for 3 weeks attenuated the development of hypertension in both the Dahl salt-sensitive (DS) rat (an insulin-resistant model of hypertension) and the one-kidney, one clip rat (a model of hypertension not associated with insulin resistance). Based on euglycemic insulin clamp studies in conscious animals, the glucose clearance rate was increased (P < .05) in pioglitazone-treated DS rats (36 +/- 3 mg/kg per minute) compared with control DS rats (27 +/- 1 mg/kg per minute). However, pioglitazone did not affect the glucose clearance rate in one-kidney, one clip hypertensive rats. Metformin, an unrelated agent that also improves glucose tolerance, had no significant effect on blood pressure or glucose clearance rate in either DS or one-kidney, one clip rats. Thus, the hypotensive effect of pioglitazone is not invariably associated with its capacity to improve insulin-induced glucose utilization.

Hybridization of matrix-bound MM-creatine kinase with BB-creatine kinase and arginine kinase

Dimeric rabbit muscle creatine kinase (MM-CK) was bound to CNBr-activated Sepharose 4B by one of its subunits (MM-CKA). Treatment of MM-CKA with guanidine hydrochloride released the unbound subunit to yield the matrix-bound monomer (M-CKB). M-CKB recombined with dissociated MM-CK soluble subunits to reconstitute a matrix-bound dimer (MM-CKC). M-CKB also associated with dissociated subunits of BB-CK from crude extracts of rabbit brain and of arginine kinase from sea cucumber muscle (MM-AK) to form the matrix-bound heterohybrids MB-CKC and M-CK/M-AKC, respectively. Guanidine hydrochloride gradient elution studies showed that MM-CKA, MM-CKC and MB-CKC were all dissociated at the same concentration of the denaturant (0.96 M), while the M-CK/M-AKC heterohybrid was less stable, dissociating at 0.5 M. The specific interaction between subunits of echinoderm and mammalian phosphagen kinases to form a hybrid enzyme of dual substrate specificity supports the view that these enzymes had a common evolutionary origin.

Pioglitazone attenuates hypertension and inhibits growth of renal arteriolar smooth muscle in rats

Hypertension is frequently associated with insulin resistance. We evaluated the effects of pioglitazone, an agent that increases insulin sensitivity, on the development of hypertension in the Dahl salt-sensitive (Dahl-S) rat and in the one-kidney, one-clip Sprague-Dawley rat. We also evaluated the effects of pioglitazone on growth of cultured preglomerular renal arteriolar smooth muscle cells. In Dahl-S rats fed a 3% NaCl diet, tail systolic blood pressures and direct arterial pressures were lower (P < 0.05) in pioglitazone-treated (20 mg/kg daily by gavage for 3 wk) than in control rats (n = 10 rats/group). In one-kidney, one-clip Sprague-Dawley rats, systolic blood pressures were also lower in pioglitazone-treated animals (P < 0.0001). In vitro, proliferation of arteriolar smooth muscle cells was stimulated (P < 0.01) by insulin, epidermal growth factor (EGF), and fetal calf serum (FCS); pioglitazone (5 microM) reversibly inhibited (P < 0.01) insulin-, EGF-, and FCS-induced proliferation. Pioglitazone (0.01-100 microM) also inhibited insulin- (1 mU/ml), EGF- (100 ng/ml), and 5% FCS-induced [3H]thymidine incorporation in a concentration-dependent manner (P < 0.01). Thus pioglitazone attenuated the development of hypertension in the Dahl-S rat and the one-kidney, one-clip rat. The ability of pioglitazone to inhibit growth of vascular smooth muscle may contribute to its hypotensive effect.

Gel filtration behaviour of arginase in frog liver and kidney extracts

The molecular weight of arginase, determined by gel filtration of frog (Rana tigerina) liver and kidney extracts, varied with the protein concentration. It increased from about 25-27 KDa in dilute solutions to about 92-96 KDA in concentrated extracts. In addition, an arginase with a molecular weight of 45-49 KDA appeared at intermediate concentrations. The results suggest the probable aggregation of arginase monomers to yield the dimeric and tetrameric forms of the enzyme at high protein concentration in extracts.

Dietary sodium chloride increases blood pressure in obese Zucker rats

In the rat, elevated arterial pressure is not consistently associated with obesity. The purpose of this study was to compare measurements of blood pressure, cardiac output, and total peripheral resistance in obese and lean Zucker rats on different NaCl intakes. Obese and lean rats drank either water or isotonic NaCl for 18 days. Tail systolic blood pressures of saline-drinking obese rats were higher than all other groups (p less than 0.05). NaCl intake did not affect blood pressure in lean rats, and blood pressures of water-drinking obese rats did not differ from those of lean controls. In a subsequent experiment, direct arterial pressures and cardiac outputs (thermodilution) were measured in separate groups of conscious rats that had been maintained on a 1% or 4% NaCl intake for 12 weeks. Arterial pressure was higher (p less than 0.01) in obese rats fed 4% NaCl (130 +/- 4 mm Hg) than in obese rats fed 1% NaCl (118 +/- 2 mm Hg) or than in lean rats fed either NaCl intake (118 +/- 3 mm Hg and 116 +/- 3 mm Hg, respectively). Cardiac output of obese rats was higher than that of lean rats (p less than 0.01); however, the NaCl-induced increase of blood pressure was accounted for by an increase of peripheral resistance (p less than 0.01). Thus, in contrast to the lean Zucker rat, arterial pressure of the obese Zucker rat is increased by a high dietary intake of NaCl.

Hemodynamic effects of high dietary intakes of sodium or chloride in the Dahl salt-sensitive rat

In the Dahl salt-sensitive (Dahl-S) rat, a high sodium without chloride diet (NaAA) and a chloride without sodium diet ("X"Cl) do not increase arterial pressure to the same extent as a high NaCl diet. To explain these differences, hemodynamic responses to acute volume expansion were compared in conscious Dahl-S and Dahl salt-resistant (Dahl-R) rats fed either 7% NaCl, NaAA, or "X"Cl diets for 5 weeks. Before acute volume expansion, on each of the three diets, mean arterial pressures and total peripheral resistances were higher (p less than 0.01) in Dahl-S than in Dahl-R rats, and in Dahl-S, arterial pressure was higher (p less than 0.05 or less) on the 7% NaCl intake than on the other two diets. No group differences were found in cardiac index (thermodilution). Right atrial pressure was also elevated (p less than 0.01) in Dahl-S rats on the 7% NaCl diet. In response to acute volume expansion, arterial pressure did not change, and the decrement of total peripheral resistance was greater in Dahl-S rats than in Dahl-R rats on each of the three diets (p less than 0.05 or less). Assuming that reductions of peripheral resistance in response to acute volume expansion reflect withdrawal of sympathetic tone, these results suggest that sympathetic tone is increased comparably on each of the diets in Dahl-S rats. As suggested by the increased right atrial pressure, higher arterial pressure induced by 7% NaCl may be related to an expanded intravascular volume in conjunction with increased neural activity.

Presence of a partial urea cycle in the leech, Poecilobdella granulosa

Ornithine carbamoyltransferase (OCT) and arginase, but not arginine synthetase (AS), were detected in the body wall and gut tissues of the leech. The activities of these enzymes were not altered by starvation. The high activity of arginase in body wall is probably due to the association of the latter with botryoidal tissue. Hirudineans, which evolved from oligochaete ancestors, appear to have lost the citrulline-arginine segment of the urea cycle due to their ammonotelic mode of nitrogen excretion.

Interaction in vitro of scallop muscle arginine kinase with filamentous actin

Scallop muscle arginine kinase binds to F-actin from mollusc and rabbit muscle in vitro. One site of interaction appears to be located in residues 305-325 of a C-terminal fragment (residues 285-375) of actin. The binding is hindered in the presence of arginine, Mg(2+)-ADP and NO3-, which form a dead-end complex with the enzyme. F-actin inhibits the enzyme activity non-competitively with respect to Mg(2+)-ATP. As a function of arginine concentration, the inhibition is of the mixed type, where Km is affected more than Vmax.

Seminoma of the testis in a patient with 48,XXYY variant of Klinefelter's syndrome

We believe this is the first reported case of seminoma in a patient with the 48,XXYY variant form of Klinefelter's syndrome. Moreover, the seminoma in this patient occurred in a normally descended testis. We report this case because patients with 48,XXYY Klinefelter's syndrome are often confined to institutions, where the diagnosis of testicular tumor may not be recognized as readily.

Effect of dietary NaCl on norepinephrine turnover in the Dahl rat

To evaluate neural mechanisms in salt-sensitive hypertension, norepinephrine turnover rates were measured in peripheral tissues and selected brain areas of Dahl salt-sensitive and salt-resistant rats receiving either 1% or 7% NaCl diets for 5 weeks. Norepinephrine turnover was determined by measuring tissue norepinephrine in untreated animals or in separate groups killed 2, 4, 6, and 10 hours after alpha-methyl-tyrosine. Plasma volume (radiolabeled albumin) was also measured. Arterial pressure of Dahl S rats receiving 7% NaCl (167 +/- 4 mm Hg) was higher (p less than 0.001) than that of Dahl S rats receiving 1% NaCl (141 +/- 3mm Hg), which was higher (p less than 0.001) than that of Dahl R rats receiving both NaCl intakes. Norepinephrine turnover was increased (p less than 0.01) by 7% NaCl in both heart and brown adipose tissue in Dahl S rats, whereas norepinephrine turnover in Dahl R rats was decreased (p less than 0.01) by the 7% NaCl intake in the heart and kidney. On the high NaCl intake, norepinephrine turnover in heart and adipose tissue was lower (p less than 0.05) in Dahl R rats than in Dahl S rats. In brain stem tissue, with the 1% NaCl diet, norepinephrine turnover was higher (p less than 0.001) in Dahl S rats than in Dahl R rats, and norepinephrine turnover was inhibited (p less than 0.001) by the high NaCl intake in Dahl S rats but not in Dahl R rats. In posterior hypothalamus, norepinephrine turnover was inhibited (p less than 0.01) by the high NaCl intake in Dahl R rats but not in Dahl S rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Purification and properties of two molecular forms of arginine kinase from the adductor muscle of the scallop, Pecten maximus

1. Two molecular forms of arginine kinase, AK1 and AK2 have been purified from the adductor muscle of the scallop, Pecten maximus. AK2 was retained on a DEAE-cellulose column at pH 7.5, but AK1 was not. 2. Both forms were monomeric (mol. wt. approximately 42,000) and showed the same pH optimum (7.5-8.0) in the direction of phosphoarginine synthesis. 3. AK1 had slower electrophoretic mobility at pH 8.3 towards the anode, higher lysine content, lower glutamate content, lower Km for L-arginine and higher Km for Mg(2+)-ATP than AK2. Unlike AK1, AK2 was strongly inhibited at high concentrations of Mg(2+)-ATP. 4. Both molecular forms cross-reacted with antisera raised against native as well as performic acid-oxidized lobster muscle arginine kinase. However, AK1 showed a greater affinity than AK2 to anti-lobster arginine kinase antibodies, particularly to those raised against the native enzyme.

Allantoin excretion in snakes

Allantoin, which is generally regarded as absent in the excreta of snakes, has been demonstrated in the urinary deposits of 7 species of snakes by a sensitive paper chromatographic method. It appears that allantoin is the end product of purine catabolism in these animals.

Effect of linoleic acid infusion on blood pressure in normotensive and hypertensive rats

High dietary intake of linoleic acid lowers arterial pressure, and, in vitro, linoleic acid inhibits the enzymatic activity of renin. The purpose of the present study was 1) to evaluate the effect of intravenous infusion of linoleic acid on blood pressure in normotensive and hypertensive Sprague-Dawley rats and 2) to determine whether the hypotensive response to linoleic acid infusion is caused by inhibition of circulating renin. Blood pressure was decreased (P less than 0.01) by linoleic acid infusion in normotensive sodium chloride-deprived animals and in animals with two-kidney, one-clip hypertension. In contrast, linoleic acid infusion did not affect blood pressure in normotensive rats on a "normal" or high sodium chloride intake, in rats with deoxycorticosterone acetate (DOCA)-salt hypertension, and in anephric rats. In sodium chloride-deprived rats, the reduction of blood pressure by linoleic acid infusion was associated with increased plasma renin activity (P less than 0.05); serum angiotensin-converting enzyme activity was unchanged. The in vitro enzymatic activity of exogenous renin in plasma of anephric rats was not affected by linoleic acid infusion. In two-kidney, one-clip hypertensive animals, pretreatment with indomethacin did not alter the hypotensive response to linoleic acid. Thus, although linoleic acid infusion lowered blood pressure in high renin but not in low renin states, the reduction of blood pressure was not related to inhibition of circulating renin or to alterations of endogenous prostaglandin biosynthesis.

Effects of cyclodiene compounds on calcium pump activity in rat brain and heart

The in vitro and in vivo effects of aldrin, dieldrin, and endrin on calmodulin regulated Ca2+-pump activity in rat brain synaptosomes and heart sarcoplasmic reticulum were investigated. All the 3 cyclodiene compounds inhibited both brain synaptosomal and heart sarcoplasmic reticulum Ca2+-pump activity in vitro in a concentration dependent manner. Calmodulin depleted Ca2+-pump activity was insensitive to the action of toxic compounds. Oral administration of pesticides (0.5-10 mg/kg) to rats similarly decreased the Ca2+-pump activity, in addition to decreasing the levels of calmodulin of both brain and heart thus indicating disruption in membrane Ca2+ transport mechanisms. Exogenous addition of calmodulin (1-20 micrograms) could effectively reverse the pesticide induced inhibition. Ca2+-pump activity is more sensitive to the 3 cyclodiene compounds in brain than in heart. The results of the present study indicate that the cyclodiene compounds may produce neurotoxic effects by altering calmodulin regulated calcium dependent events in neurons.

Failure of salt loading to inhibit tissue norepinephrine turnover in prehypertensive Dahl salt-sensitive rats

To determine if alterations of electrolyte balance or sympathetic nervous system activity are present in Dahl salt-sensitive rats (DS) before the onset of hypertension, we compared electrolyte balances, extracellular fluid volume (inulin space), plasma volume (radiolabeled albumin), and norepinephrine turnover in peripheral tissues (heart and interscapular brown fat) in prehypertensive DS and Dahl salt-resistant rats (DR). Animals were maintained for 5 to 7 days on either a "normal" or high NaCl diet. Tissue norepinephrine turnover was evaluated by measuring the rate at which norepinephrine content decreased following tyrosine hydroxylase inhibition with alpha-methyl-p-tyrosine. Blood pressure was higher (p less than 0.05) in DS (135 +/- 2 [SE] mm Hg) than in DR (129 +/- 2 mm Hg) and was not affected by the diets. Extracellular fluid volume and net Na+ and Cl- balances did not differ between DS and DR. However, plasma volume was greater in DS than in DR (p less than 0.05). In both fat and heart, norepinephrine turnover was decreased by dietary NaCl loading in DR (p less than 0.01), but not in DS. Thus, the tendency of the DS to become hypertensive with high NaCl intake may be related to the combined effects of an increased plasma volume and the failure of high dietary NaCl to inhibit peripheral sympathetic nervous system activity.

Arginine:glycine amidinotransferase. A comparative study in lizard and mouse tissues

Kidney transamidinase activity in the lizard (Calotes versicolor), like that in the mouse, showed the pH optimum at 7.4. The lizard enzyme was inhibited to a greater degree than the mouse enzyme at high concentrations (greater than 20 mM) of L-arginine and glycine. Kidney and liver in the lizard and kidney and pancreas in the mouse were the tissues with high transamidinase activity. While transamidinase activity was widely distributed in mouse tissues, the enzyme was found to be restricted only to a few tissues in the lizard. Hydrocortisone administration into male lizards did not significantly alter the transamidinase levels in kidney and liver.

A comparative polyacrylamide gel electrophoretic study of arginase in vertebrate tissues

The electrophoretic behaviour of arginase in the tissue extracts of rat, beef, lizard and frog was studied by bidirectional polyacrylamide gel electrophoresis. The enzyme from rat liver and submaxillary gland migrated to the cathode with the activity concentrated in a single peak. Arginase from beef liver emerged as a single peak of anodal migration with a significant shoulder in the sample gel. Frog liver and kidney enzymes also appeared as single peaks with a distinct anodal movement. The activity in mammalian kidney and lizard liver and kidney resolved into two peaks of anodal migration suggesting the presence of two isoenzymes of arginase in these tissues.

Inhibition of creatine kinase by iodoalkanes. Further appraisal of the essential nature of the reactive thiol group

Creating kinase (ATP: creatine N-phosphotransferase) is completely inhibited by low molecular weight iodoalkanes in a pseudo first order reaction. Analysis of this and other data suggests that covalent modification per se is not a sufficient criterion to establish whether or not an enzyme group is essential for catalysis.

Enzymic basis for the nutritional requirement of arginine in insects

The fat body of the cockroach, Blaberus cranifera, and the silkmoth, Hyalophora gloveri, has been tested for some enzymes of the urea cycle. While ornithine transcarbamoylase and argininosuccinase activities could not be detected, arginase is present in the fat body of these insects. These results explain the essentiality of arginine in the diet of insects.

The inhibition of arginase from the hepatopancreas of a terrestrial snail by amino acids

The effects of L-amino acids on arginase from the hepatopancreas of the snail Ariophanta (=Cryptozona) ligulata were studied. This enzyme was inhibited by ornithine, valine, lysine, leucine, isoleucine, proline and threonine. The other amino acids were without any significant effect. Only ornithine was a non-competitive inhibitor, where as all the other inhibitory amino acids were competitive.